Method and apparatus for low density parity check channel coding in wireless communication system

ABSTRACT

A low density parity check (LDPC) channel encoding method is used in a wireless communications system. A communication device encodes an input bit sequence by using an LDPC matrix, to obtain an encoded bit sequence for transmission. The LDPC matrix is obtained based on a lifting factor Z and a base matrix. The base matrix may be one of eight exemplary designs. The encoding method can be used in various communications systems including fifth generation (5G) telecommunication systems, and can support various encoding requirements for information bit sequences with different code lengths.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/566,331, filed on Sep. 10, 2019, which is a continuation ofInternational Application No. PCT/CN2017/092878, filed on Jul. 13, 2017.The International Application claims priority to Chinese PatentApplication No. 201710454030.3, filed on Jun. 15, 2017 and ChinesePatent Application No. 201710503056.2, filed on Jun. 27, 2017. All ofthe aforementioned applications are hereby incorporated by reference intheir entireties.

TECHNICAL FIELD

Embodiments of the present application relate to the communicationfield, and in particular, to an information processing method and acommunication apparatus.

BACKGROUND

Low density parity check (LDPC) code is a type of linear block codeincluding a sparse check matrix, and is characterized by a flexiblestructure and low decoding complexity. Because decoding the LDPC codeuses a partially parallel iterative decoding algorithm, the LDPC codehas a higher throughput than a conventional turbo code. The LDPC codemay be used as an error-correcting code in a communication system, so asto increase channel transmission reliability and power utilization. LDPCcode may further be widely applied to space communication, fiber opticcommunication, a personal communication system, an asymmetric digitalsubscriber line (ADSL), a magnetic recording device, and the like. TheLDPC code scheme has been currently considered as one of channel codingschemes in the fifth generation mobile communication systems.

In practical applications, LDPC matrices characterized by differentspecial structures may be used. An LDPC matrix H, having a specialstructure, may be obtained by expanding an LDPC base matrix having aquasi cyclic (QC) structure.

Generally, lengths of to-be-encoded information bit sequences vary fromtens to hundreds of bits, and code rates required by a communicationsystem are also flexibly variable. How to support encoding oninformation bit sequences of various lengths, to satisfy code raterequirements of a system becomes a problem that needs to be resolved.

SUMMARY

Embodiments of the present application provide an information processingmethod, a communication apparatus, and a communication system, tosupport encoding and decoding of information bit sequences of variouslengths and meet flexible code length and code rate requirements of thecommunication system.

According to a first aspect, an encoding method and an encoder areprovided. The encoder encodes an input sequence by using a low-densityparity-check (LDPC) matrix.

According to a second aspect, a decoding method and a decoder areprovided. The decoder decodes an input sequence by using a low-densityparity-check (LDPC) matrix.

In a first implementation of the first aspect or the second aspect, theLDPC matrix is obtained based on a base graph, and the base graphincludes submatrix A, submatrix B, submatrix C, submatrix D, andsubmatrix E, where

the submatrix A is a matrix including m_(A) rows and n_(A) columns,m_(A) and n_(A) are positive integers, 4≤m_(A)≤7, and n_(A)=10;

the submatrix B is a matrix including m_(A) rows and m_(A) columns, andthe submatrix B includes a column whose weight is 3 and a submatrix B′having a bi-diagonal structure;

the submatrix D includes m_(D) rows in a matrix F, the matrix F is amatrix including m_(F) rows and (m_(A)+n_(A)) columns, m_(D) and m_(F)are positive integers, 0≤m_(D)≤m_(F), and 35≤m_(F)≤38;

the submatrix C is an all zero matrix including m_(A) rows and m_(D)columns; and the submatrix E is an identity matrix including m_(D) rowsand m_(D) columns.

Based on the foregoing implementation, in a possible implementation, anytwo adjacent rows in the last 10 rows in the base graph are mutuallyorthogonal.

Based on the foregoing implementations, in a possible implementation,the last 10 rows in the base graph include at least five groups, each ofthe at least five groups includes at least two rows, and the at leasttwo rows are mutually orthogonal.

Based on any of the foregoing implementations, in a possibleimplementation, in the matrix F, weights of nine rows are 3, and aweight of one row is 2.

In a design, in the matrix F, a weight of one column is 16, a weight ofone column is 18, a weight of one column is 11, weights of two columnsare 10, a weight of one column is 9, a weight of one column is 8, aweight of one column is 7, a weight of one column is 6, weights of twocolumns are 4, a weight of one column is 3, and weights of two columnsare 2.

Based on the first implementation, in another possible implementation, arow count of rows having an orthogonal structure in the matrix F isgreater than or equal to 10, and in the matrix F, a weight of one columnis 16, a weight of one column is 18, a weight of one column is 11,weights of two columns are 10, a weight of one column is 9, a weight ofone column is 8, a weight of one column is 7, a weight of one column is6, weights of two columns are 4, a weight of one column is 3, andweights of two columns are 2.

In another design, in the matrix F, weights of nine rows are 3, and aweight of one row is 2.

In another design, the matrix F includes at least 10 rows, and any twoadjacent rows in the at least 10 rows are mutually orthogonal.

In another design, the matrix F includes at least five groups, each ofthe at least five groups includes at least two rows, and the at leasttwo rows are mutually orthogonal. Optionally, the at least two rows maybe consecutive rows. For example, the at least 10 rows may be the last10 rows in a base graph 30 a.

In any of the foregoing implementations, if m_(A)>4, weights of columnsother than m_(A) columns in the matrix F is 0.

For example, 10 rows having the orthogonal structure in the matrix F mayinclude, for example, rows or columns of a matrix block including row 25to row 34 and column 0 to column 13 in the base graph 30 a; or 10 rowshaving the orthogonal structure in the matrix F may include, forexample, rows or columns of a matrix block including row 25 to row 34and column 0 to column 16 in the base graph 30 a. In the matrix F, rowsmay be switched with each other, and columns may also be switched witheach other.

Based on the foregoing implementations, a base matrix of the base graph30 a may be, for example, any one of base matrices 30 b-1, 30 b-2, 30b-3, 30 b-4, 30 b-5, 30 b-6, 30 b-7, and 30 b-8, or a matrix obtained byperforming row/column permutation on any one of base matrices 30 b-1, 30b-2, 30 b-3, 30 b-4, 30 b-5, 30 b-6, 30 b-7, and 30 b-8.

Based on the foregoing implementations, a shift matrix of the matrix Fmay be a matrix including row 7 to row 41 and column 0 to column 16 inany matrix of 30 b-1 to 30 b-8, or a matrix obtained by performingrow/column permutation on the matrix including row 7 to row 41 andcolumn 0 to column 16 in any matrix of 30 b-1 to 30 b-8; or a shiftmatrix of the matrix F may include a matrix including row 4 to row 41and column 0 to column 14 in any matrix of 30 b-1 to 30 b-8, or a matrixobtained by performing row/column permutation on the matrix includingrow 4 to row 41 and column 0 to column 14 in any matrix of 30 b-1 to 30b-8.

To support different code block lengths, the LDPC code utilizesdifferent lifting factors Z. Based on the foregoing implementations, ina possible implementation, based on the different lifting factors Z,base matrices corresponding to the different lifting factors Z are used.For example, Z=a×2^(j), where a ϵ {2, 3, 5, 7, 9, 11, 13, 15}.

If the lifting factor is one satisfying Z=2×2^(j), where j=0, 1, 2, 3,4, 5, 6, 7, the shift matrix of the matrix F may be the matrix includingrow 7 to row 41 and column 0 to column 16 in 30 b-1, or the matrixobtained by performing the row/column permutation on the matrixincluding row 7 to row 41 and column 0 to column 16 in 30 b-1; or theshift matrix of the matrix F may be the matrix including row 4 to row 41and column 0 to column 14 in 30 b-1, or the matrix obtained byperforming row/column permutation on the matrix including row 4 to row41 and column 0 to column 14 in 30 b-1. Correspondingly, the base matrixof the base graph 30 a may be the matrix shown in 30 b-1, or the matrixobtained by performing row/column permutation on the matrix shown in 30b-1.

If the lifting factor is one satisfying Z=3×2^(j), where j=0, 1, 2, 3,4, 5, 6, 7, the shift matrix of the matrix F may be the matrix includingrow 7 to row 41 and column 0 to column 16 in 30 b-2, or the matrixobtained by performing row/column permutation on the matrix includingrow 7 to row 41 and column 0 to column 16 in 30 b-2; or the shift matrixof the matrix F may be the matrix including row 4 to row 41 and column 0to column 14 in 30 b-2, or the matrix obtained by performing row/columnpermutation on the matrix including row 4 to row 41 and column 0 tocolumn 14 in 30 b-2. Correspondingly, the base matrix of the base graph30 a may be the matrix shown in 30 b-2, or the matrix obtained byperforming row/column permutation on the matrix shown in 30 b-2.

If the lifting factor is one satisfying Z=5×2^(j), where j=0, 1, 2, 3,4, 5, 6, the shift matrix of the matrix F may be the matrix includingrow 7 to row 41 and column 0 to column 16 in 30 b-3, or the matrixobtained by performing row/column permutation on the matrix includingrow 7 to row 41 and column 0 to column 16 in 30 b-3; or the shift matrixof the matrix F may be the matrix including row 4 to row 41 and column 0to column 14 in 30 b-3, or the matrix obtained by performing row/columnpermutation on the matrix including row 4 to row 41 and column 0 tocolumn 14 in 30 b-3. Correspondingly, the base matrix of the base graph30 a may be the matrix shown in 30 b-3, or the matrix obtained byperforming row/column permutation on the matrix shown in 30 b-3.

If the lifting factor satisfying one in Z=7×2^(j), where j=0, 1, 2, 3,4, 5, the shift matrix of the matrix F may be the matrix including row 7to row 41 and column 0 to column 16 in 30 b-4, or the matrix obtained byperforming row/column permutation on the matrix including row 7 to row41 and column 0 to column 16 in 30 b-4; or the shift matrix of thematrix F may be the matrix including row 4 to row 41 and column 0 tocolumn 14 in 30 b-4, or the matrix obtained by performing row/columnpermutation on the matrix including row 4 to row 41 and column 0 tocolumn 14 in 30 b-4. Correspondingly, the base matrix of the base graph30 a may be the matrix shown in 30 b-4, or the matrix obtained byperforming row/column permutation on the matrix shown in 30 b-4.

If the lifting factor is one satisfying Z=9×2^(j), where j=0, 1, 2, 3,4, 5, the shift matrix of the matrix F may be the matrix including row 7to row 41 and column 0 to column 16 in 30 b-5, or the matrix obtained byperforming row/column permutation on the matrix including row 7 to row41 and column 0 to column 16 in 30 b-5; or the shift matrix of thematrix F may be the matrix including row 4 to row 41 and column 0 tocolumn 14 in 30 b-5, or the matrix obtained by performing row/columnpermutation on the matrix including row 4 to row 41 and column 0 tocolumn 14 in 30 b-5. Correspondingly, the base matrix of the base graph30 a may be the matrix shown in 30 b-5, or the matrix obtained byperforming row/column permutation on the matrix shown in 30 b-5.

If the lifting factor is one satisfying Z=11×2^(j), where j=0, 1, 2, 3,4, 5, the shift matrix of the matrix F may be the matrix including row 7to row 41 and column 0 to column 16 in 30 b-6, or the matrix obtained byperforming row/column permutation on the matrix including row 7 to row41 and column 0 to column 16 in 30 b-6; or the shift matrix of thematrix F may be the matrix including row 4 to row 41 and column 0 tocolumn 14 in 30 b-6, or the matrix obtained by performing row/columnpermutation on the matrix including row 4 to row 41 and column 0 tocolumn 14 in 30 b-6. Correspondingly, the base matrix of the base graph30 a may be the matrix shown in 30 b-6, or the matrix obtained byperforming row/column permutation on the matrix shown in 30 b-6.

If the lifting factor is one satisfying Z=13×2^(j), where j=0, 1, 2, 3,4, the shift matrix of the matrix F may be the matrix including row 7 torow 41 and column 0 to column 16 in 30 b-7, or the matrix obtained byperforming row/column permutation on the matrix including row 7 to row41 and column 0 to column 16 in 30 b-7; or the shift matrix of thematrix F may be the matrix including row 4 to row 41 and column 0 tocolumn 14 in 30 b-7, or the matrix obtained by performing row/columnpermutation on the matrix including row 4 to row 41 and column 0 tocolumn 14 in 30 b-7. Correspondingly, the base matrix of the base graph30 a may be the matrix shown in 30 b-7, or the matrix obtained byperforming row/column permutation on the matrix shown in 30 b-7.

If the lifting factor is one satisfying Z=15×2^(j), where j=0, 1, 2, 3,4, the shift matrix of the matrix F may be the matrix including row 7 torow 41 and column 0 to column 16 in 30 b-8, or the matrix obtained byperforming row/column permutation on the matrix including row 7 to row41 and column 0 to column 16 in 30 b-8; or the shift matrix of thematrix F may be the matrix including row 4 to row 41 and column 0 tocolumn 14 in 30 b-8, or the matrix obtained by performing row/columnpermutation on the matrix including row 4 to row 41 and column 0 tocolumn 14 in 30 b-8. Correspondingly, the base matrix of the base graph30 a may be the matrix shown in 30 b-8, or the matrix obtained byperforming row/column permutation on the matrix shown in 30 b-8.

Further, optionally, based on the foregoing implementations, for thelifting factors Z, an element P_(i,j)=f(V_(i,j),Z) in row i and column jin the base matrix of Z may further be obtained according to the basematrices of the foregoing sets, where V_(i,j) is an element in row i andcolumn j in the base matrix of the set to which the lifting factor Zbelongs.

For example,

$P_{i,j} = \left\{ {\begin{matrix}{- 1} & {V_{i,j} = {- 1}} \\{{mod}\left( {V_{i,j},Z} \right)} & {V_{i,j} \geq 0}\end{matrix}.} \right.$

In another possible implementation, the base graph or the base matrixmay further include at least one column corresponding to built-inpuncture bits.

In the foregoing implementations, the base graph and the base matrix ofthe LDPC matrix may satisfy performance requirements of code blockswhose block length are 20 to 2560 bits.

Based on the foregoing aspects or any possible implementation of theaspects, in another possible implementation, the method furtherincludes: determining the lifting factor Z. For example, a value of thelifting factor Z is determined according to a length K of the inputsequence. For example, if the length of the input sequence is K, aminimum value satisfying 10×Z≥K may be determined from a plurality oflifting factors defined in a system.

Optionally, the LDPC matrix may be obtained based on the base matrixcorresponding to Z, or based on a shift matrix corresponding to Z.

For a communication device at a transmit end, the encoding an inputsequence by using an LDPC matrix includes:

encoding the input sequence by using an LDPC matrix corresponding to thelifting factor Z; or encoding the input sequence by using a matrix,wherein the matrix is obtained by performing row/column permutation onan LDPC matrix corresponding to the lifting factor Z. In thisapplication, the row/column permutation refers to row permutation,column permutation, or row permutation and column permutation.

For a communication device at a receive end, the decoding an inputsequence by using an LDPC matrix includes:

decoding the input sequence by using an LDPC matrix corresponding to thelifting factor Z; or performing row/column permutation on an LDPC matrixcorresponding to the lifting factor Z, and decoding the input sequenceby using a matrix obtained by performing row/column permutation on anLDPC matrix corresponding to the lifting factor Z. In this application,the row/column permutation refers to row permutation, columnpermutation, or row permutation and column permutation.

In a possible implementation, the LDPC matrix may be stored in thememory, and the input sequence is encoded by using the LDPC matrix; oran LDPC matrix that may be used for encoding is obtained by performingpermutation (row/column permutation) or lifting based on the LDPCmatrix.

In another possible implementation, parameters may be stored in thememory, and an LDPC matrix used for encoding or decoding may be obtainedaccording to the parameters, so that the input sequence may be encodedor decoded based on the LDPC matrix. The parameters include at least oneof the following: a base graph, a base matrix, a permutated matrixobtained by performing row/column permutation on the base graph or thebase matrix, a lifted matrix based on the base graph or the base matrix,a shift value of a non-zero-element in the base matrix, or any parameterrelated to the obtaining the LDPC matrix.

In still another possible implementation, the base matrix of the LDPCmatrix may be stored in a memory.

In still another possible implementation, the base graph of the LDPCmatrix is stored in a memory, and shift values of non-zero-elements inthe base matrix of the LDPC matrix may be stored in the memory.

Based on the foregoing possible implementations, in a possible design,at least one of a base graph and a base matrix that are used for LDPCencoding or decoding is obtained by performing row permutation, columnpermutation, or row permutation and column permutation on at least oneof the base graph and the base matrices of the LDPC matrix.

According to a third aspect, a communication apparatus is provided. Thecommunication apparatus may include corresponding modules configured toperform the foregoing method designs. The modules may be software and/orhardware.

In a possible design, the communication apparatus provided in the thirdaspect includes a processor and a transceiver component, and theprocessor and the transceiver component may be configured to implementfunctions in the foregoing encoding or decoding method. In this design,if the communication apparatus is a terminal, a base station, or othernetwork devices, the transceiver component of the communicationapparatus may be a transceiver. If the communication apparatus is abaseband chip or a baseband processing board, the transceiver componentof the communication apparatus may be an input/output circuit of thebaseband chip or the baseband processing board, and is configured toreceive/send an input/output signal. The communication apparatus mayoptionally include a memory, configured to store data and/or aninstruction.

In an implementation, the processor may include the encoder according tothe foregoing first aspect and a determining unit. The determining unitis configured to determine a lifting factor Z required for encoding theinput sequence. The encoder is configured to encode the input sequenceby using the LDPC matrix corresponding to the lifting factor Z.

In another implementation, the processor may include the decoderaccording to the foregoing second aspect and an obtaining unit. Theobtaining unit is configured to obtain soft values of the LDPC code anda lifting factor Z. The decoder is configured to decode the soft valuesof the LDPC code based on a base matrix H_(B) corresponding to thelifting factor Z, to obtain an information bit sequence.

According to a fourth aspect, a communication apparatus is provided. Thecommunication apparatus includes one or more processors.

In a possible design, the one or more processors may implement afunction of the encoder in the first aspect. In another possible design,the encoder in the first aspect may be a part of the processor. Inaddition to the function of the encoder in the first aspect, theprocessor may further implement other functions.

In a possible design, the one or more processors may implement afunction of the decoder in the second aspect. In another possibledesign, the decoder in the second aspect may be a part of the processor.

Optionally, the communication apparatus may further include atransceiver and an antenna.

Optionally, the communication apparatus may further include a componentconfigured to produce a transport block cyclic redundancy check (CRC), acomponent used for code block segmentation and CRC attachment, aninterleaver used for interleaving, a modulator used for modulationprocessing, or the like.

Optionally, the communication apparatus may further include ademodulator used for a demodulation operation, a deinterleaver used fordeinterleaving, a component used for de-rate matching, or the like.Functions of the components may be implemented by using the one or moreprocessors.

In a possible design, functions of the components may be implemented byusing the one or more processors.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic diagram of a base graph and a base matrix of anLDPC code, and circular permutation matrices of the base matrix in anLDPC code scheme;

FIG. 2 is a schematic structural diagram of a base graph of an LDPCcode;

FIG. 3a is a schematic diagram of a base graph of an LDPC code accordingto an embodiment of the present application;

FIG. 3b -1 to FIG. 3b -8 show schematic diagrams of base matrices of thebase graph shown in FIG. 3 a;

FIG. 4 is a performance graph according to an embodiment of the presentapplication;

FIG. 5 is a schematic structural diagram of an information processingapparatus according to an embodiment of the present application; and

FIG. 6 is a schematic diagram of a communication system according to anembodiment of the present application.

DESCRIPTION OF EMBODIMENTS

To facilitate understanding, some terms in this application aredescribed below.

In this application, terms “network” and “system” are usuallyinterchanged, and terms “apparatus” and “device” are also usuallyinterchanged. However, a person skilled in the art may understand theirmeanings. A “communication apparatus” may be a chip (such as a basebandchip, or a digital signal processing chip, or a general-purpose chip), aterminal, a base station, or other network devices. The terminal is adevice having a communication function. The terminal may include ahandheld device, an in-vehicle device, a wearable device, and acomputing device that have a wireless communication function, or anotherprocessing device connected to a wireless modem, or the like. Theterminal may have different names in different networks, for example,user equipment, a mobile station, a user unit, a station, a cellularphone, a personal digital assistant, a wireless modem, a wirelesscommunication device, a handheld device, a laptop computer, a cordlesstelephone set, and a wireless local loop station. For ease ofdescription, in this application, the devices are referred to as theterminal for short. The base station (BS), also referred to as a basestation device, is a device deployed in a radio access network toprovide a wireless communication function. In different radio accesssystems, names of the base station may be different. For example, a basestation in a Universal Mobile Telecommunication System (UMTS) network isreferred to as a node B (NodeB), a base station in a Long-Term Evolution(LTE) network is referred to as an evolved node B (eNB, or eNodeB), abase station in a new radio (NR) network is referred to as atransmission reception point (TRP) or a next-generation node B (gNB), ora base station in various other networks may also be referred to asother names. The present application is not limited thereto.

The following describes technical solutions in embodiments of thepresent application with reference to the accompanying drawings.

Usually, an LDPC code can be defined by using a parity check matrix H.The parity check matrix H for the LDPC code may be obtained by using abase graph and shift values. Usually, the base graph may include m×nmatrix elements (entry). The base graph may be represented by using amatrix including m rows and n columns. The value of each matrix elementis either 0 or 1. An element whose value is 0 is also referred to as azero-element sometimes, which may be replaced with an all zero matrix ofsize Z×Z. An element whose value is 1 is also referred to as anon-zero-element sometimes, which may be replaced with a circularpermutation matrix (circulant permutation matrix) of size Z×Z. That is,each matrix element represents an all zero matrix or a circularpermutation matrix. FIG. 1 shows an example 10a of a base graph of anLDPC code in which m=4 and n=20 and that has a QC structure. It shouldbe noted that in this specification, row indexes and column indexes of abase graph and a matrix are all numbered starting from 0. This is onlyfor ease of understanding. It may be understood that the row indexes andthe column indexes may alternatively be numbered starting from 1, andcorresponding row indexes and column indexes are increased by 1 based onthe row indexes and the column indexes shown in this specification.

If a value of an element in row i and column j in the base graph is 1,it is assigned a shift value P_(i,j). P_(i,j) is an integer greater thanor equal to 0, and it indicates that the element of 1 (anon-zero-element) in row i and column j may be replaced with a circularpermutation matrix of size Z×Z corresponding to P_(i,j). The circularpermutation matrix may be obtained by circularly shifting an identitymatrix of size Z×Z to the right for P_(i,j) times. It will beappreciated that in the base graph, each element whose value is 0 isreplaced with an all zero matrix of size Z×Z, and each element whosevalue is 1 is replaced with a circular permutation matrix of size Z×Zcorresponding to a shift value of the element, so that the parity checkmatrix of the LDPC code can be obtained. The base graph may be used toindicate positions of shift values, and each non-zero-element in thebase graph corresponds to a shift value. Z is a positive integer, mayalso be referred to as a lifting factor, and may also be referred to asa lifting size, a lifting factor, or the like sometimes. Z may bedetermined according to a code block size that is supported by a systemand size of information data. It will be appreciated that the paritycheck matrix H has a size of (m×Z)×(n×Z). For example, if the liftingfactor Z=4, each zero element is replaced with a 4×4 all zero matrix 11a. If P_(2,3)=2, a non-zero-element in row 2 and column 3 is replacedwith a 4×4 circular permutation matrix 11 d. The matrix is obtained bycircularly shifting a 4×4 identity matrix 11 b to the right twice. IfP_(2,4)=0, a non-zero-element in row 2 and column 4 is replaced with theidentity matrix 11 b. It should be noted that only examples aredescribed herein, and the examples do not constitute a limitation.

Value of P_(i,j) may depend on the lifting factor Z. Therefore, for anelement of 1 (a non-zero-element) in row i and column j of the basegraph, P_(i,j) may be different for different lifting factors Z. Forease of implementation, usually, an m×n base matrix is defined in thesystem. Each element in the base matrix is in a one-to-onecorrespondence with each element in the base graph. A zero-element inthe base graph has a same position in the base matrix, and the elementis indicated by −1. A non-zero-element indicated by 1 in row i andcolumn j in the base graph has a same position in the base matrix, andthe non-zero-element is indicated by a value V_(i,j), where V_(i,j) maybe a shift value defined relative to a preset or a particular liftingfactor Z, for example, a shift value relative to a maximum liftingfactor Z_(max) in a set to which the lifting factor Z belongs. In thisway, V_(i,j) may be a shift value of the non-zero-element in row i andcolumn j when the maximum lifting factor Z_(max) in the set to which Zbelongs is used. In this embodiment of this application, the base matrixis also referred to as a shift matrix of a matrix of the base graphsometimes.

P_(i,j) may be obtained based on V_(i,j) and Z. For example, it may beexpressed as P_(i,j)=f(V_(i,j),Z), where f(V_(i,j),Z) is a functionusing V_(i,j) and Z as parameters. For example,

$P_{i,j} = \left\{ {\begin{matrix}{- 1} & {V_{i,j} = {- 1}} \\{{mod}\left( {V_{i,j},Z} \right)} & {V_{i,j} \geq 0}\end{matrix}.} \right.$

As shown in FIG. 1, 10 b is a base matrix corresponding to the basegraph 10 a.

Usually, the base graph or the base matrix of the LDPC code may includep columns corresponding to built-in puncture bits, where p may be aninteger from 0 to 2. These columns may be used in encoding, butsystematic bits corresponding to the built-in puncture bits are notsent. A code rate of the base matrix of the LDPC code satisfiesR=(n−m)/(n−p). For a base matrix including 4 rows and 20 columns (4×20),if there are two columns corresponding to built-in puncture bits, a coderate is (20−4)/(20−2)=8/9.

For an LDPC code used in a wireless communication system, a matrix of abase graph of the LDPC code has a size of m×n, and the base graph mayinclude five submatrices: A, B, C, D, and E. A weight of the matrix isdetermined by a quantity of non-zero-elements, a row weight of a row (arow weight) refers to a quantity of non-zero-elements in the row, and acolumn weight of a column (a column weight) refers to a quantity ofnon-zero-elements in the column.

As shown in 200 in FIG. 2, submatrix A is a matrix including m_(A) rowsand n_(A) columns, and the submatrix A has a size of m_(A)×n_(A). Eachcolumn corresponds to Z systematic bits in the LDPC code, and asystematic bit is sometimes referred to as an information bit.

Submatrix B is a square matrix of m_(A) rows and m_(A) columns, and thesubmatrix B has a size of m_(A)×m_(A). Each column corresponds to Zparity bits in the LDPC code. As shown in 20 a of FIG. 2, the submatrixB includes a submatrix B′ with a bi-diagonal structure, and a matrixcolumn whose weight is 3 (for short, weight-3 column), and the weight-3column may be located at the left side of the submatrix B′. Thesubmatrix B may further include one or more matrix columns whose columnweights are 1 (for short, weight-1 column). For example, a possibleimplementation is shown in 20 b or 20 c in FIG. 2.

Generally, a matrix generated based on the submatrices A and B is a corematrix, which may be used to support high-code rate encoding.

Continuing in FIG. 2, submatrix C is an all zero matrix, and thesubmatrix C has a size of m_(A)×m_(D). Submatrix E is an identitymatrix, and the submatrix E has a size of m_(D)×m_(D).

Submatrix D has a size of m_(D)×(n_(A)+m_(A)), and the submatrix D maybe used to generate parity bits with low code rate.

It may be understood that the base graph is described above from amathematical definition perspective. Because submatrix C is an all zeromatrix and submatrix E is an identity matrix, in a possibleimplementation, a matrix including the submatrix A and submatrix B, or amatrix including the submatrix A, the submatrix B, and the submatrix Dmay be used to represent a base graph of a matrix in encoding ordecoding.

Because structures of the submatrix C and the submatrix E are relativelyfixed, structures of the submatrix A, the submatrix B, and the submatrixD are determining factors affecting encoding and decoding performance ofthe LDPC code.

When an LDPC matrix with a raptor-like structure is used for encoding,in a possible implementation, the part of the matrix including thesubmatrix A and the submatrix B, namely, a core matrix, may be firstused for encoding to obtain one or more parity bits corresponding to thesubmatrix B. Then the entire matrix is used for encoding to obtain oneor more parity bits corresponding to the submatrix E. Because thesubmatrix B may include a submatrix B′ with a bi-diagonal structure anda weight-1 column. Therefore, during the encoding, one or more paritybits corresponding to the bi-diagonal structure may be first obtained,and then one or more parity bits corresponding to the weight-1 columnare obtained.

The following provides an example of encoding method. Assuming that thecore matrix including the submatrix A and the submatrix B is H_(core), aweight-1 column and a row in which a non-zero-element in the weight-1column is located are removed from the H_(core) to obtain a matrixH_(core-dual). A matrix block in the H_(core-dual) corresponding toparity bits is represented by H_(e)=[H_(e1) H_(e2)], where H_(e1) is aweight-3 column, and H_(e2) has a bi-diagonal structure. According to adefinition of an LDPC code matrix, H_(core-dual)·[S P_(e)]^(T)=0, whereS is an input sequence and is a vector including information bits, P_(e)is a vector including parity bits, and [S P_(e)]^(T) indicates atransposed matrix including the input sequence S and P_(e). Therefore,parity bits corresponding to H_(core-dual) may be calculated firstaccording to the input sequence S and H_(core-dual). The input sequenceS includes all information bits. Then, parity bits corresponding to theweight-1 column in the submatrix B is calculated according to theobtained parity bits corresponding to H_(core-dual) and the inputsequence S. In this case, all parity bits corresponding to the submatrixB may be obtained. Then, parity bits corresponding to the submatrix E isobtained by encoding using the submatrix D and based on the inputsequence S and the obtained parity bits corresponding to the submatrixB. In this way, all the information bits and all parity bits areobtained. These bits form an encoded sequence, that is, LDPCcodeword(s).

Optionally, LDPC encoding may further include shortening and puncturingoperations. The shortened bits and the punctured bits are not sent.

The shortening is usually performed starting from the last bit ofinformation bits, and may be performed in different manners. Forexample, for a quantity of shortened bits is s₀, the last s₀ bits in theinput sequence S may be set as known bits, such as set to 0 or null orother values, to obtain an input sequence S′, and then the inputsequence S′ is encoded by using an LDPC matrix. For another example, thelast (s₀ mod Z) bits in the input sequence S may be set as known bits,such as set to 0 or null or other values, to obtain an input sequenceS′, and the last

$\left\lfloor \frac{s_{0}}{Z} \right\rfloor$

columns in the submatrix A are deleted to obtain an LDPC matrix H′, andthe input sequence S′ is encoded by using the LDPC matrix H′, or thelast

$\left\lfloor \frac{s_{0}}{Z} \right\rfloor$

columns in the submatrix A do not participate in encoding of the inputsequence S′. After the encoding is completed, the shortened bits are notsent.

The puncturing may be performed on one or more columns corresponding tobuilt-in puncture bits, or one or more parity bits in an input sequence.Usually puncturing one or more parity bits is also from the last one bitin parity bits. Alternatively, puncturing parity bit(s) may be performedaccording to a preset puncturing pattern in the system. In a possibleimplementation, an input sequence is first encoded, and then based on aquantity p of bits that need to be punctured, the last p bit(s) inparity bits are selected, or p bit(s) are selected according to thepreset puncturing pattern in the system, where the p bit(s) are notsent. In another possible implementation, p column(s) of a matrixcorresponding to the punctured bits and p rows in whichnon-zero-elements in these columns are located may be determined, andthe rows and the columns do not participate in encoding, and thereforeno corresponding parity bits are generated.

It should be noted that the encoding implementations described hereinare merely used as examples. Other known encoding implementations mayalternatively be used based on the base graph and/or the base matrixprovided in this application. and the encoding implementations are notlimited in this application. Decoding in this application may beperformed in various decoding methods, for example, a min-sum (MS)decoding method, or a belief propagation decoding method. The MSdecoding method may also be referred to as a flood MS decoding methodsometimes. For example, an input sequence is initialized, and aniteration is performed. Hard decision detection is performed after theiteration, and a hard decision result is checked. If the decoding resultmeets a check equation, decoding succeeds, the iteration ends, and thedecision result is output. If the decoding result does not meet a checkequation, an iteration is performed again within a maximum quantity ofiteration times. If the check still fails when the maximum quantity ofiteration times is reached, the decoding fails. It may be understoodthat the principle of the MS decoding is conventionally known, anddetails are not described herein again.

It should be noted that the decoding method is merely used as an exampleherein, other decoding methods known may alternatively be used based onthe base graph and/or the base matrix provided in this application, andthe decoding manner is not limited in this application.

An LDPC code may be obtained based on a base graph and a base matrix, anupper limit of performance of the LDPC code may be determined byperforming density evolution on the base graph or the base matrix. Anerror floor of the LDPC code is determined based on a shift value in thebase matrix. Improving encoding performance and decoding performance andlowering the error floor are some of objectives of designing the basegraph and the base matrix. In the wireless communication system, codelengths are widely varied. For example, a code length may be 40 bits,1280 bits, or the like. FIG. 3a and FIG. 3b -1 to FIG. 3b -8 areexamples of a base graph and base matrices of a core matrix of the LDPCcode. The examples may meet performance requirements of code blockshaving a block length of 20 to 2560 bits. For ease of description andunderstanding, column indexes and row indexes are respectively shown onthe uppermost side and the leftmost side in FIG. 3a and FIG. 3b -1 toFIG. 3b -8.

FIG. 4 is a performance diagram based on the LDPC code shown in FIG. 3aand FIG. 3b -1 to FIG. 3b -8. An LDPC 1 indicates an LDPC code obtainedby encoding based on a base matrix corresponding to a base graph 30 a,and LDPC 2 indicates a commonly used LDPC code used for comparison. Ahorizontal coordinate indicates a length of an information bit sequence,and a unit of length is bit. A vertical coordinate indicates a symbolsignal-to-noise ratio (Es/N0). Performance curves indicates performanceof a symbol signal-to-noise ratio for the LDPC 1 and the LDPC 2 in caseof different information bit sequence lengths when a block error rate(BLER) is 0.0001. It will be appreciated that at a same BLER, a symbolsignal-to-noise ratio of the LDPC 1 is less than that of the LDPC 2 incase of different information bit sequence lengths, that is, performanceof the LDPC 1 is better than that of the LDPC 2.

FIG. 3a shows an example of a base graph 30 a of an LDPC code. Thematrix of the base graph 30 a has 42 rows and 52 columns. In the figure,0 to 51 in the uppermost row indicate column indexes, and 0 to 41 in theleftmost column indicate row indexes.

In the base graph 30 a, submatrix A corresponds to systematic bits andhas m_(A) rows and 10 columns, where 4≤m_(A)≤7. For example, if m_(A)=4,the submatrix A includes elements in row 0 to row 3 and column 0 tocolumn 9 in the base graph 30 a. For another example, if m_(A)>4, usingm_(A)=7 as an example, the submatrix A includes elements in row 0 to row6 and column 0 to column 9 in the base graph 30 a.

Submatrix B corresponds to parity bits, has m_(A) rows and m_(A)columns, and includes elements in row 0 to row (m_(A)−1) and column 10to column (10+m_(A)−1) in the base graph 30 a.

The submatrix A and the submatrix B form a core matrix of the base graphof an LDPC code, that is, a matrix including m_(A) rows and(m_(A)+n_(A)) columns. The matrix may be used for high-code rateencoding. For ease of description, using m_(A)=7 as an example below,the core matrix of the base graph of the LDPC code is 7 rows and 17columns.

The submatrix A may include two columns corresponding to built-inpuncture bits. After puncturing, a code rate that can be supported bythe core matrix is 10/(17−2)=⅔.

The submatrix B includes one weight-3 column, that is, a column weightof column 0 of the submatrix B (column 10 of the core matrix) is 3. Amatrix including column 1 to column 3 (column 11 to column 13 in thecore matrix) and row 0 to row 3 in the submatrix B is of a bi-diagonalstructure. The submatrix B further includes three weight-1 columns.

Using m_(A)=7 as an example, the core matrix of the base graph 30 aincludes two rows whose weights are 10, two rows whose weights are 8,two rows whose weights are 6, and one row whose weight is 4. That is,row weights of rows in the core matrix including the submatrix A and thesubmatrix B are respectively 8, 10, 8, 10, 4, 6, and 6. It should benoted that the rows in the core matrix may be switched, for example, row0 is switched with row 2, row 1 is switched with row 3, and the like.Each of the rows in the core matrix may be one of rows shown in row 0 torow 6 and column 0 to column 16 in the core matrix of the base graph 30a. The rows may be switched with each other, and the columns may also beswitched with each other. For example, column 8 may be switched withcolumn 14 in the core matrix. It should be noted that, only examples areprovided herein. In an actual application, column permutation and rowpermutation may be flexibly designed based on a system requirement.

It may be understood that because in a matrix, rows may be switched witheach other, columns may also be switched with each other, rowpermutation does not change weights of columns, and column permutationdoes not change weights of rows, a quantity of non-zero-elements in thematrix does not change. After row permutation and column permutation,weights of rows in a base graph do not change. Use of a base graphobtained after row permutation, column permutation, or row permutationand column permutation does not affect performance.

It should be noted that in this application, that performance is notaffected means: On the whole, impact is acceptable and falls within atolerance range. For example, in some scenarios or in some ranges, theperformance is lowered in an allowable range. However, in some scenariosor some ranges, the performance is improved. On the whole, there islittle impact on the performance.

Usually, for a given base graph or a given base matrix of an LDPC code,impact on performance caused by few modifications to matrix elements isacceptable. For example, in an implementation, few modifications may bemade based on the core matrix of the base graph 30 a. For example, aweight of one row is greater than or equal to 2 and less than or equalto 5, and weights of other six rows are greater than or equal to 6 andless than or equal to 12. It may be understood that referring to thesolution provided in this application, weights of some rows may beincreased or decreased by 1 or 2. This is not limited in thisapplication.

To obtain flexible code rates, a submatrix C, a submatrix D, and asubmatrix E of corresponding sizes may be added based on the corematrix. Because the submatrix C is an all zero matrix and the submatrixE is an identity matrix, sizes of the matrices are determined accordingto code rates, and structures of the matrices are relatively fixed.Encoding performance and decoding performance are mainly affected by thecore matrix and the submatrix D. Different code rates may be obtained byadding rows and columns based on the core matrix to form thecorresponding submatrices C, D, and E. For example, the core matrix ofthe base graph 30 a may be used as the core matrix, and thecorresponding submatrices C, D, and E are added to satisfy requirementsof encoding or decoding for different code rates.

A column count m_(D) of the submatrix D is a sum of a column count ofthe submatrix A and a column count of the submatrix B, and a row countof the submatrix D is mainly related to a code rate. Using the basegraph 30 a as an example, if m_(A)=4, a corresponding column count ofthe submatrix D is (n_(A)+m_(A))=14, or if m_(A)=7, a correspondingcolumn count of the submatrix D is (n_(A)+m_(A))=17. If a code ratesupported by the LDPC code is R_(m), a base graph or a base matrix ofthe LDPC code has a size of m×n, where n=n_(A)/R_(m)+p andm=n−n_(A)=n_(A)/R_(m)+p−n_(A). If a minimum code rate R_(m)=⅕, and aquantity p columns corresponding to the built-in puncture bits is 2,using the base graph 30 a as an example, n=52 and m=42. A row countm_(D) of the submatrix D may be up to m−m_(A)=42−m_(A), and if m_(A)=4,0≤m_(D)≤38, or if m_(A)=7, 0≤m_(D)≤35.

For ease of description, a matrix F of m_(F) rows and (m_(A)+n_(A))columns may be defined, so that the submatrix D may include m_(D) rowsin the matrix F, where 0≤m_(D)≤m_(F) , and 35≤m_(F)≤38. Still usingm_(A)=7 as an example, in the base graph 30 a, m_(A)+m_(D)=42. Ifm_(D)=35, correspondingly, the submatrix D includes 35 rows and 17columns. To be specific, the submatrix D is the matrix F, and the coderate supported by the corresponding LDPC code is 10/50=⅕. It will beappreciated that for m_(A)=7, a matrix including row 7 to row 41 andcolumn 0 to column 17 in the base graph 30 a is the matrix F. Form_(A)=4, a matrix including row 4 to row 41 and column 0 to column 13 inthe base graph 30 a is the matrix F. It should be noted that, onlyexamples are provided herein, and the present application is not limitedthereto. m_(A) may alternatively be any integer value from 4 to 7, andthe column count of the matrix F also correspondingly changes.

In the present application, if there is at most one non-zero-element ina same column in two adjacent rows in the base graph, the two rows aremutually orthogonal. In other columns different from some columns fortwo adjacent rows in the base graph, if there is at most onenon-zero-element in a same column of the other columns for two adjacentrows in the base graph, the two rows are quasi-orthogonal.

The matrix F may include a plurality of rows having a quasi-orthogonalstructure and at least two rows having an orthogonal structure. Forexample, the matrix F includes at least 15 rows satisfying thequasi-orthogonal structure. In columns other than the f columnscorresponding to built-in puncture bits in any two adjacent rows in the15 rows, there is at most one non-zero-element in a same column, thatis, a matrix block including the columns other than the columnscorresponding to built-in puncture bits in the at least 15 rows in thematrix F has an orthogonal structure. The matrix F may further include10 to 20 rows satisfying the orthogonal structure. In these rows, thereis at most one non-zero-element in a same column in any two adjacentrows. To be specific, there is also at most one non-zero-element in abuilt-in puncture column.

For example, using the base graph 30 a as an example, the last 10 rowsin the matrix F has an orthogonal structure, weights of nine rows are 3,and a weight of one row is 2. Column weight distribution of the matrix Fmay be: a weight of one column is 16, a weight of one column is 18, aweight of one column is 11, weights of two columns are 10, a weight ofone column is 9, a weight of one column is 8, a weight of one column is7, a weight of one column is 6, weights of two columns are 4, a weightof one column is 3, and weights of two columns are 2. If m_(A)>4,weights of other columns in the matrix F are 0.

Using m_(A)=7 as an example, in an example of the matrix F in the basegraph 30 a, row weights of the matrix F are 5, 3, 4, 4, 4, 3, 4, 4, 3,4, 4, 3, 3, 3, 3, 2, 3, 3, 2, 4, 2, 3, 2, 4, 2, 3, 3, 3, 3, 3, 2, 3, 3,3, and 3 in sequence.

Because the submatrix E is an identity matrix, weights of rows in thebase graph 30 a are respectively 8, 10, 8, 10, 4, 6, 6, 6, 4, 5, 5, 5,4, 5, 5, 4, 5, 5, 4, 4, 4, 4, 3, 4, 4, 3, 5, 3, 4, 3, 5, 3, 4, 4, 4, 4,4, 3, 4, 4, 4, and 4.

Still using m_(A)=7 as an example, if m_(D)=15, the submatrix D in thebase graph of the LDPC code may include 15 rows and 17 columns. Thesubmatrix D may be a matrix including row 0 to row 14 in the matrix F inthe base graph 30 a, that is, row 7 to row 21, and column 0 to column 16in the base graph 30 a. A code rate supported by the corresponding LDPCcode is 10/30=⅓. That is, at the code rate, the base graph of the LDPCcode corresponds to a matrix including row 0 to row 21 and column 0 tocolumn 31 in the base graph 30 a. The submatrix E is an identity matrixincluding 15 rows and 15 columns, and the submatrix C is an all zeromatrix including 7 rows and 15 columns.

If m_(D)=25, the submatrix D in the base graph of the LDPC code has 25rows and 17 columns. The submatrix D may be a matrix including row 0 torow 24 in the matrix F in the base graph 30 a, that is, row 7 to row 31,and column 0 to column 16 in the base graph 30 a. A code rate supportedby the corresponding LDPC code is 10/40=¼. That is, at the code rate,the base graph of the LDPC code corresponds to a matrix including row 0to row 31 and column 0 to column 41 in the base graph 30 a. Thesubmatrix E is an identity matrix including 25 rows and 25 columns, andthe submatrix C is an all zero matrix including 7 rows and 25 columns.

The rest can be deduced by analogy, and details are not described one byone.

It should be noted that in the base graph and the base matrix of theLDPC code, rows may be switched with each other, and columns may also beswitched with each other. For example, in the base graph 30 a, row 34may be switched with row 36, and column 44 may be switched with column45. For another example, the submatrix D includes m_(D) rows in thematrix F, the m_(D) rows may not be switched, or one or more of them_(D) rows may be switched, the submatrix E is still of a diagonalstructure, and neither row permutation nor column permutation isperformed on the submatrix E. For example, row 27 is switched with row29 in the matrix F, the submatrix D includes m_(D) rows in the matrix F,and the submatrix E is still of the diagonal structure. The matrix F isa quasi-orthogonal matrix before the row permutation, and is still aquasi-orthogonal matrix by performing row permutation. It may beunderstood that if the base graph or the base matrix includes thesubmatrix D, when columns in the core matrix are switched, correspondingcolumns in the submatrix D also need to be switched.

As shown in FIG. 3b -1 to FIG. 3b -8, base matrices 30 b-1 to 30 b-8 areexamples of a plurality of base matrices of the base graph 30 a.Anon-zero-element in row i and column j in the base graph 30 a has asame position in each of the base matrices 30 b-1 to 30 b-8, and a valueof the non-zero-element is a shift value V_(i,j). A zero-element in ashift matrix is represented by using −1 or null. A part corresponding tothe submatrix D in the base matrix may include m_(D) rows in a shiftmatrix of the matrix F, and values of m_(D) may be selected according todifferent code rates. A shift matrix corresponding to the submatrix Dincludes m_(D) rows in the shift matrix of the matrix F.

In a possible implementation, the shift matrix of the matrix F may be amatrix including row 7 to row 41 and column 0 to column 16 in any one ofmatrices 30 b-1 to 30 b-8, or a matrix obtained by performing row/columnpermutation on the matrix including row 7 to row 41 and column 0 tocolumn 16 in any one of matrices 30 b-1 to 30 b-8; or the shift matrixof the matrix F may include a matrix including row 4 to row 41 andcolumn 0 to column 14 in any one of matrices 30 b-1 to 30 b-8, or amatrix obtained by performing row/column permutation on the matrixincluding row 4 to row 41 and column 0 to column 14 in any one ofmatrices 30 b-1 to 30 b-8.

To support different block lengths, the LDPC code utilizes differentlifting factors Z. For example, lifting factors Z=a×2^(j), where a ϵ {2,3, 5, 7, 9, 11, 13, 15} may be divided into eight sets shown in Table 1:

TABLE 1 Set 1 Z = 2 × 2^(j), where j = 0, 1, 2, 3, 4, 5, 6, 7 Set 2 Z =3 × 2^(j), where j = 0, 1, 2, 3, 4, 5, 6, 7 Set 3 Z = 5 × 2^(j), where j= 0, 1, 2, 3, 4, 5, 6 Set 4 Z = 7 × 2^(j), where j = 0, 1, 2, 3, 4, 5Set 5 Z = 9 × 2^(j), where j = 0, 1, 2, 3, 4, 5 Set 6 Z = 11 × 2^(j),where j = 0, 1, 2, 3, 4, 5 Set 7 Z = 13 × 2^(j), where j = 0, 1, 2, 3, 4Set 8 Z = 15 × 2^(j), where j = 0, 1, 2, 3, 4

To ensure LDPC code performance in different block lengths, based on thesets of different lifting factors Z, base matrices corresponding to thesets of the different lifting factors Z may be separately used.

In a possible implementation:

If the lifting factor Z is one lifting factor in the set 1, the shiftmatrix of the matrix F may be the matrix including row 7 to row 41 andcolumn 0 to column 16 in 30 b-1, or the matrix obtained by performingrow/column permutation on the matrix including row 7 to row 41 andcolumn 0 to column 16 in 30 b-1; or the shift matrix of the matrix F maybe the matrix including row 4 to row 41 and column 0 to column 14 in 30b-1, or the matrix obtained by performing row/column permutation on thematrix including row 4 to row 41 and column 0 to column 14 in 30 b-1.Correspondingly, the base matrix of the base graph 30 a may be thematrix shown in 30 b-1, or the matrix obtained by performing row/columnpermutation on the matrix shown in 30 b-1.

If the lifting factor Z is one lifting factor in the set 2, the shiftmatrix of the matrix F may be the matrix including row 7 to row 41 andcolumn 0 to column 16 in 30 b-2, or the matrix obtained by performingrow/column permutation on the matrix including row 7 to row 41 andcolumn 0 to column 16 in 30 b-2; or the shift matrix of the matrix F maybe the matrix including row 4 to row 41 and column 0 to column 14 in 30b-2, or the matrix obtained by performing row/column permutation on thematrix including row 4 to row 41 and column 0 to column 14 in 30 b-2.Correspondingly, the base matrix of the base graph 30 a may be thematrix shown in 30 b-2, or the matrix obtained by performing row/columnpermutation on the matrix shown in 30 b-2.

If the lifting factor Z is one lifting factor in the set 3, the shiftmatrix of the matrix F may be the matrix including row 7 to row 41 andcolumn 0 to column 16 in 30 b-3, or the matrix obtained by performingrow/column permutation on the matrix including row 7 to row 41 andcolumn 0 to column 16 in 30 b-3; or the shift matrix of the matrix F maybe the matrix including row 4 to row 41 and column 0 to column 14 in 30b-3, or the matrix obtained by performing row/column permutation on thematrix including row 4 to row 41 and column 0 to column 14 in 30 b-3.Correspondingly, the base matrix of the base graph 30 a may be thematrix shown in 30 b-3, or the matrix obtained by performing row/columnpermutation on the matrix shown in 30 b-3.

If the lifting factor Z is one lifting factor in the set 4, the shiftmatrix of the matrix F may be the matrix including row 7 to row 41 andcolumn 0 to column 16 in 30 b-4, or the matrix obtained by performingrow/column permutation on the matrix including row 7 to row 41 andcolumn 0 to column 16 in 30 b-4; or the shift matrix of the matrix F maybe the matrix including row 4 to row 41 and column 0 to column 14 in 30b-4, or the matrix obtained by performing row/column permutation on thematrix including row 4 to row 41 and column 0 to column 14 in 30 b-4.Correspondingly, the base matrix of the base graph 30 a may be thematrix shown in 30 b-4, or the matrix obtained by performing row/columnpermutation on the matrix shown in 30 b-4.

If the lifting factor Z is one lifting factor in the set 5, the shiftmatrix of the matrix F may be the matrix including row 7 to row 41 andcolumn 0 to column 16 in 30 b-5, or the matrix obtained by performingrow/column permutation on the matrix including row 7 to row 41 andcolumn 0 to column 16 in 30 b-5; or the shift matrix of the matrix F maybe the matrix including row 4 to row 41 and column 0 to column 14 in 30b-5, or the matrix obtained by performing row/column permutation on thematrix including row 4 to row 41 and column 0 to column 14 in 30 b-5.Correspondingly, the base matrix of the base graph 30 a may be thematrix shown in 30 b-5, or the matrix obtained by performing row/columnpermutation on the matrix shown in 30 b-5.

If the lifting factor Z is one lifting factor in the set 6, the shiftmatrix of the matrix F may be the matrix including row 7 to row 41 andcolumn 0 to column 16 in 30 b-6, or the matrix obtained by performingrow/column permutation on the matrix including row 7 to row 41 andcolumn 0 to column 16 in 30 b-6; or the shift matrix of the matrix F maybe the matrix including row 4 to row 41 and column 0 to column 14 in 30b-6, or the matrix obtained by performing row/column permutation on thematrix including row 4 to row 41 and column 0 to column 14 in 30 b-6.Correspondingly, the base matrix of the base graph 30 a may be thematrix shown in 30 b-6, or the matrix obtained by performing row/columnpermutation on the matrix shown in 30 b-6.

If the lifting factor Z is one lifting factor in the set 7, the shiftmatrix of the matrix F may be the matrix including row 7 to row 41 andcolumn 0 to column 16 in 30 b-7, or the matrix obtained by performingrow/column permutation on the matrix including row 7 to row 41 andcolumn 0 to column 16 in 30 b-7; or the shift matrix of the matrix F maybe the matrix including row 4 to row 41 and column 0 to column 14 in 30b-7, or the matrix obtained by performing row/column permutation on thematrix including row 4 to row 41 and column 0 to column 14 in 30 b-7.Correspondingly, the base matrix of the base graph 30 a may be thematrix shown in 30 b-7, or the matrix obtained by performing row/columnpermutation on the matrix shown in 30 b-7.

If the lifting factor Z is one lifting factor in the set 8, the shiftmatrix of the matrix F may be the matrix including row 7 to row 41 andcolumn 0 to column 16 in 30 b-8, or the matrix obtained by performingrow/column permutation on the matrix including row 7 to row 41 andcolumn 0 to column 16 in 30 b-8; or the shift matrix of the matrix F maybe the matrix including row 4 to row 41 and column 0 to column 14 in 30b-8, or the matrix obtained by performing row/column permutation on thematrix including row 4 to row 41 and column 0 to column 14 in 30 b-8.Correspondingly, the base matrix of the base graph 30 a may be thematrix shown in 30 b-8, or the matrix obtained by performing row/columnpermutation on the matrix shown in 30 b-8.

For example, a value of the lifting factor Z is determined based on alength K of the input sequence. For example, if the length of the inputsequence is K, a minimum value that meets 10×Z≥K may be determined froma plurality of lifting factors defined in a system and used as the valueof the lifting factor of the matrix. Further, a corresponding basematrix may be selected according to the determined lifting factor.

Similarly, rows in the base matrix may also be switched with each other,and columns in the base matrix may also be switched with each other. Ifat least one of row permutation or column permutation is performed onthe base graph, same permutation is also performed on the correspondingrows or columns in the base matrix.

It may be understood that in this application, the quasi-orthogonalstructure is not limited to only two adjacent rows. A matrix includingthe quasi-orthogonal structure may alternatively be designed to includea plurality of groups, each group includes at least two rows, forexample, 3 rows or 4 rows, and rows included in each group arequasi-orthogonal.

In the performance curve diagram shown in FIG. 4, LDPC 1 indicates thatthe LDPC code is obtained by encoding based on a base matrixcorresponding to the base graph 30 a, and LDPC 2 indicates a commonlyused LDPC code used for comparison. A horizontal coordinate indicates alength of an information bit sequence, and a unit of length is bit. Avertical coordinate is a symbol signal-to-noise ratio (Es/N0).Performance curves indicate performance of a symbol signal-to-noiseratio for LDPC 1 and LDPC 2 in case of different information bitsequence lengths when BLER is 0.0001. It will be appreciated that at asame BLER, a symbol signal-to-noise ratio of LDPC 1 is less than that ofLDPC 2 in case of different information bit sequence lengths, that is,performance of LDPC 1 is better than that of LDPC 2.

In an encoding method provided in an embodiment of the presentapplication, an encoder encodes an input sequence by using an LDPCmatrix. A base graph of the LDPC matrix may be any base graph in theforegoing examples, and a base matrix of the LDPC matrix may be any basematrix in the foregoing examples. The input sequence of the encoder maybe an information bit sequence, or may be an information bit sequenceobtained through at least one type of the following processing: CRC bitsattachment or filler bits insertion.

Further, the method includes: determining a lifting factor Z. A value ofthe lifting factor Z may be determined based on a length K of the inputsequence. The information bit sequence may also be referred to as a codeblock (code block) sometimes, and may be obtained through code blocksegmentation on a transport block. If the length of the information bitsequence is K, a minimum value that meets 10×Z≥K may be determined froma plurality of lifting factors defined in a system as the value of thelifting factor Z. For example, if K=128 and the lifting factors definedin the system include lifting factors in the sets in Table 1, forexample, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 18, 20, 22,24, 26, 28, 30, 32, 36, 40, 44, 48, 52, 56, 60, 64, 72, 80, 88, 96, 104,112, 120, 128, 144, 160, 176, 192, 208, 224, 240, and 256, it may bedetermined that Z is 13 and is in the set 7. It should be noted thatonly examples are provided herein, and the examples do not constitute alimitation.

In another possible design, Kb may be a column count of columnscorresponding to information bits in a base matrix of an LDPC code. In asupported lifting factor set, a minimum value Z₀ that meets Kb·Z₀≥K maybe determined as the value of the lifting factor Z. In the base graph 30a, the column count Kb_(max) of columns corresponding to informationbits is 10, and it is assumed that a lifting factor set supported by thebase graph 30 a is {24, 26, 28, 30, 32, 36, 40, 44, 48, 52, 56, 60, 64,72, 80, 88, 96, 104, 112, 120, 128, 144, 160, 176, 192, 208, 224, 240,256, 288, 320, 352, 384}.

If the length K of the input sequence is 529 bits, Z is 26. If thelength K of the input sequence is 5000 bits, Z is 240. It should benoted that only examples are provided herein, and the examples do notconstitute a limitation.

For another example, a value of Kb may also vary with a value of K, butthe value of Kb does not exceed the column count of columnscorresponding to the information bits in the base matrix of the LDPCcode. For example, different thresholds may be set for Kb.

A possible design is as follows: It should be noted that thresholdvalues 640, 560, or 192 herein are only examples. Other values may bedesigned according to a system design requirement.

if (K>640), Kb=10;

elseif (K>560), Kb=9;

elseif (K>192), Kb=8;

else Kb=6; end

Wherein the lifting factor Z may be determined by the encoder accordingto the length K of the input sequence, or may be obtained by the encoderfrom other entities (such as a processor).

In a possible design, a value of a filler bit may be null, or 0, orother values defined in a system. After encoding, the filler bits can beidentified and are not sent. The present application is not limitedthereto.

The encoding, by the encoder, an input sequence by using an LDPC matrixH may be encoding the input sequence by using the LDPC matrix Hcorresponding to the lifting factor Z.

In a possible implementation, an input sequence is c={c₀, c₁, c₂, . . ., c_(K-1)}, a length of the input sequence c is K, and an outputsequence obtained after the input sequence c is encoded by the encoderis d={d₀, d₁, d₂, . . . , d_(N-1)}, where K is an integer greater than0, and K may be an integer multiple of the lifting factor Z.

The output sequence d includes K₀ bits in the input sequence c andparity bits in a parity bit sequence w, where K₀ is an integer greaterthan 0 and less than or equal to K. A length of the parity bit sequencew is N−K₀, where w={w₀, w₁, w₂, . . . , w_(N−K) ₀ ⁻¹}.

The parity bit sequence w and the input sequence c meet Formula (1):

$\begin{matrix}{{{H \times \begin{bmatrix}c^{T} \\w^{T}\end{bmatrix}} = 0^{T}},} & (1)\end{matrix}$

where c^(T)=[C₀, c₁, c₂, . . . , c_(K−1)]^(T), c^(T) is a transposedvector of a vector including bits in the input sequence, and w^(T)=[w₀,w₁, w₂, . . . , w_(N−K) ₀ ⁻¹]^(T), w^(T) is a transposed vector of avector including bits in the parity bit sequence, where 0^(T) is acolumn vector, and values of all elements of 0^(T) are 0.

H is an LDPC matrix obtained based on any base graph described in theforegoing embodiments, a base graph of H has m rows and n columns, andmay be the base graph 30 a mentioned in the foregoing embodiments.

In a design, the base graph of H includes p built-in puncture columns,where p is an integer greater than or equal to 0, and information bitscorresponding to the p built-in puncture columns are not output, and theoutput sequence does not include the information bits corresponding tothe p built-in puncture columns. In this case, K₀=K−p·Z. For example, ifp=2, K₀=K−2·Z and the length of the parity bit sequence w is N+2·Z−K. Ifthe p built-in puncture columns participate in encoding, K₀=K and thelength of the parity bit sequence w is N−K.

Correspondingly, H may have M rows and (N+p·Z) columns or M rows and Ncolumns, and a size of the base graph of H is: m=M/Z rows and

$n = \frac{\left( {n + {p \cdot Z}} \right)}{Z}$

columns.

The base graph of the LDPC matrix H may be represented as [H_(BG)H_(BG,EXT)], where

${H_{{BG},{EXT}} = \begin{bmatrix}0_{m_{c} \times n_{c}} \\I_{n_{c} \times n_{c}}\end{bmatrix}},$

0_(m) _(c) _(×n) _(c) represents an all zero matrix of size m_(c)×n_(c),and I_(n) _(c) _(×n) _(c) represents an identity matrix of sizen_(c)×n_(c). Because Kb may vary with K, H_(BG) includes Kb columnscorresponding to information bits in H_(BG2) and includes column 10 tocolumn (10+m_(A)−1) in H_(BG2), a column count in H_(BG2) is 10+m_(A),where 4≤m_(A)≤7. For example, if Kb ∈ {6, 8, 9}, H_(BG) may be obtainedafter column Kb to column 9 are deleted from H_(BG2). If Kb=10,H_(BG)=H_(BG2).

In a possible design, 0_(m) _(c) _(×n) _(c) is the submatrix C in thebase graph in the foregoing embodiments, and I_(n) _(c) _(×n) _(c) isthe submatrix E in the foregoing embodiments, so that

${H_{{BG}\; 2} = \begin{bmatrix}\begin{bmatrix}A & B\end{bmatrix} \\D\end{bmatrix}},$

where A, B, and D are respectively the submatrices A, B, and D in thebase graph in the foregoing embodiments. Therefore, m_(c)=7, 0≤n_(c)≤35,a row count in H_(BG2) is less than or equal to 42 and is greater thanor equal to 4, and the column count in H_(BG2) is equal to 17.

In another possible design, because column 14 to column 16 are weight-1columns and non-zero-elements in these columns are in row 4 to row 6,therefore, m_(c)=6, 0≤n_(c)≤36, and the column count in H_(BG2) is 16;or m_(c)=5, 0≤n_(c)≤37, and the column count in H_(BG2) is 15; orm_(c)=4, 0≤n_(c)≤38, and the column count in H_(BG2) is 14.

Correspondingly, the LDPC matrix H may be represented by H=[H₁ H₂].

H₁ may be obtained by replacing each zero-element in H_(BG) with an allzero matrix of size Z×Z, and replacing each non-zero-element with acircular permutation matrix h_(i,j) of size Z×Z, where the circularpermutation matrix h_(i,j) is obtained by circularly shifting anidentity matrix of size Z×Z to the right P_(i,j) times, and h_(i,j) mayalso be represented by I(P_(i,j)), where i is a row index and j is acolumn index. In a possible design, P_(i,j)=mod (V_(i,j),Z), whereV_(i,j) is a non-zero-element in row i and column j in a base matrixcorresponding to a lifting factor set index corresponding to Z.

H₂ may be obtained by replacing each zero-element in H_(BG,EXT) with anall zero matrix of size Z×Z and replacing each non-zero-element with anidentity matrix of size Z×Z.

The encoder may perform encoding and outputting in a plurality ofmanners. The base graph 30 a mentioned in the foregoing embodiments isused as an example for description below. The base graph has a maximumof 42 rows and a maximum of 52 columns, and includes two built-inpuncture columns. For ease of description, in the present application, abase graph that has the most rows and of the most columns is referred toas a complete base graph sometimes.

Manner 1

Encoding is performed based on the complete base graph, so that as manyparity bits as possible can be obtained. In this case, m=42 and n=52,which correspond to row 0 to row 41 and column 0 to column 51 in theforegoing base graph.

Correspondingly, for the LDPC matrix H, M is 42×Z, and if the outputsequence includes information bits corresponding to the columnscorresponding to built-in puncture bits, N=(42+Kb)×Z; or if the outputsequence does not include 2×Z information bits corresponding to thebuilt-in puncture bits, N=(40+Kb)·Z.

Information bits and parity bits that need to be sent may be determinedfrom the output sequence generated by the encoder during subsequentprocessing.

Manner 2

Encoding is performed based on some rows and some columns in thecomplete base graph. Rows and columns may be selected, based on a coderate that needs to be sent, or a quantity of information bits and aquantity of parity bits that need to be sent, or the like, from thecomplete base graph for encoding.

For example, the code rate is ⅔, m=7, and n=17, that is, encoding isperformed based on row 0 to row 6 and column 0 to column 16 in theforegoing base graph 30 a.

Correspondingly, for the LDPC matrix H, M=7×Z, and if the outputsequence includes information bits corresponding to the built-inpuncture columns, N=17×Z; or if the output sequence does not include theinformation bits corresponding to the built-in puncture columns, N=15×Z.

For another example, the code rate is ⅚, m=4, and n=14.

For another example, the code rate is ⅕, m=42, and n=52.

It will be appreciated that the size of the base graph of H is 4≤m≤42and 14≤n≤52. Correspondingly, for the LDPC matrix H, 4×Z

M

42×Z and (4+Kb)×Z

N

(42+Kb)×Z.

For example, if Z is 13 and in the set 7, encoding is performed on theinput sequence by using the LDPC matrix obtained based on the basematrix 3b-7 corresponding to the set 7.

In another design, an element P_(i,j) in row i and column j of the basematrix of the lifting factor Z may also satisfy the followingrelationship:

$P_{i,j} = \left\{ {\begin{matrix}{- 1} & {V_{i,j} = {- 1}} \\{{mod}\left( {V_{i,j},Z} \right)} & {V_{i,j} \geq 0}\end{matrix},} \right.$

where

-   -   V_(i,j) may be a shift value of an element in row i and column j        in a base matrix of a set to which Z belongs, that is, a shift        value of a non-zero-element in row i and column j in a base        matrix of a maximum lifting factor in the set to which Z        belongs.

For example, using an example in which Z is 13, the element P_(i,j) inrow i and column j in the base matrix of Z meets:

$P_{i,j} = \left\{ {\begin{matrix}{- 1} & {V_{i,j} = {- 1}} \\{{mod}\left( {V_{i,j},Z} \right)} & {V_{i,j} \geq 0}\end{matrix},} \right.$

where

V_(i,j) is a shift value of a non-zero-element in row i and column j inthe base matrix 3b-7.

It should be noted that only examples are provided herein, and theexamples do not constitute a limitation in the present application.

In the foregoing implementations, the base matrix H_(B) of the LDPCmatrix H may be any base matrix mentioned in the foregoing embodimentsor a base matrix obtained by performing row permutation, or columnpermutation, or row permutation and column permutation on any basematrix described above. The base graph of the LDPC matrix includes atleast a submatrix A and a submatrix B, and may further include asubmatrix C, a submatrix D, and a submatrix E. For each submatrix, referto descriptions in the foregoing embodiments, and details are notdescribed herein again. Certainly, the base matrix H_(B) mayalternatively be a base matrix which base graph is the same as the basegraph 30 a. The present application is not limited thereto.

In a possible implementation, the base matrix H_(B) of the LDPC code maybe stored in a memory, and the encoder obtains the LDPC matrixcorresponding to the lifting factor Z, to encode the input sequence. Inanother possible implementation, because there are a plurality of basematrices H_(B) of the LDPC code, relatively large storage space isoccupied when the base matrices are stored according to matrixstructures. The base graph of the LDPC code may alternatively be storedin the memory, and shift values of non-zero-elements in the basematrices may be stored row by row or column by column, and then the LDPCmatrix may be obtained based on the base graph and shift values of abase matrix corresponding to the lifting factor Z.

The base graph may indicate positions of non-zero-elements in each basematrix. In another possible implementation, storing the base graph maybe storing the positions of the non-zero-elements in the base graph. Aposition of a non-zero-element may be indicated by a row and a column inwhich the non-zero-element is located, for example, a column position ofa non-zero-element in a row, or a row position of a non-zero-element ina column. In another possible implementation, storing the base graph mayalso be storing positions of zero-elements in the base graph. Similarly,a position of a zero-element may also be indicated by a row and a columnin which the zero-element is located, for example, a column position ofa zero-element in a row is located, or a row position of a zero-elementin a column. Therefore, positions of non-zero-elements may be obtainedby excluding the positions of the zero-elements. It should be noted onlyexamples are provided herein, and the examples do not constitute alimitation in the present application.

In a design, parameters related to a base graph or a base matrix may beexpressed in a table. For example, related parameters or tables may bestored in one or more memories. Related parameters such as a row indexin the base graph or the base matrix and a column index in which anon-zero-element is located are read from the memory, so as to obtainthe base graph or the base matrix. Optionally, a row weight of each row,and a shift value of a non-zero-element in each row may be stored.

The following uses FIG. 3a as an example for description. For other basegraphs or base matrices provided in this application, refer to a similardesign.

For example, parameters in the base graph 30 a may be expressed in Table2.

TABLE 2 Row weight Column index of non-zero- Row index (row degree/rowelement (column position (row index) weight) of non-zero-element in row)0 8 0, 1, 2, 3, 6, 9, 10, 11 1 10 0, 3, 4, 5, 6, 7, 8, 9, 11, 12 2 8 0,1, 3, 4, 8, 10, 12, 13 3 10 1, 2, 4, 5, 6, 7, 8, 9, 10, 13 4 4 0, 1, 11,14 5 6 0, 1, 5, 7, 11, 15 6 6 0, 5, 7, 9, 11, 16 7 6 1, 5, 7, 11, 13, 178 4 0, 1, 12, 18 9 5 1, 8, 10, 11, 19 10 5 0, 1, 6, 7, 20 11 5 0, 7, 9,13, 21 12 4 1, 3, 11, 22 13 5 0, 1, 8, 13, 23 14 5 1, 6, 11, 13, 24 15 40, 10, 11, 25 16 5 1, 9, 11, 12, 26 17 5 1, 5, 11, 12, 27 18 4 0, 6, 7,28 19 4 0, 1, 10, 29 20 4 1, 4, 11, 30 21 4 0, 8, 13, 31 22 3 1, 2, 3223 4 0, 3, 5, 33 24 4 1, 2, 9, 34 25 3 0, 5, 35 26 5 2, 7, 12, 13, 36 273 0, 6, 37 28 4 1, 2, 5, 38 29 3 0, 4, 39 30 5 2, 5, 7, 9, 40 31 3 1,13, 41 32 4 0, 5, 12, 42 33 4 2, 7, 10, 43 34 4 0, 12, 13, 44 35 4 1, 5,11, 45 36 4 0, 2, 7, 46 37 3 10, 13, 47 38 4 1, 5, 11, 48 39 4 0, 7, 12,49 40 4 2, 10, 13, 50 41 4 1, 5, 11, 51

It should be noted that only examples are provided herein, and theexamples do not constitute a limitation. Related parameters of otherbase graph or base matrix provided in this application may also beexpressed in a similar table. It may be understood that the foregoingbase graph 30 a and Table 2 are intended to help understand designs ofthe base graph and the base matrix. Representation forms of the basegraph and the base matrix are not limited to only representation formsof the foregoing base graph 30 a and Table 2. Other possible variationsmay be included.

In an implementation, related parameters may be column index, columnweight, and row index in which a non-zero-element is located; or columnindex, column weight, and row index in which a zero-element is located.Using a form of Table 3 as an example, Table 3 shows only examples oftwo columns of the base graph. Other columns can be deduced by analogy,and details are not described one by one. Column 14 to column 51 may beweight-1 columns, and may alternatively be not stored. The row index ofa non-zero-element is calculated according to a column index.

TABLE 3 Column Column index weight Row index of non-zero-element 0 22 0,1, 2, 4, 5, 6, 8, 10, 11, 13, 15, 18, 19, 21, 23, 25, 27, 29, 32, 34,36, 39 1 23 0, 2, 3, 4, 5, 7, 8, 9, 10, 12, 13, 14, 16, 17, 19, 20, 22,24, 28, 35, 38, 41 . . . . . . . . .

In an implementation, the parameter “row weight” or “column weight” inTable 2 or Table 3 may alternatively be omitted. According to columns orrows in which non-zero-elements in a row or a column are located, aquantity of non-zero-elements in a row or a column is learned.Therefore, row weight or column weight is also learned.

In an implementation, parameter values in “Column index ofnon-zero-element ” in Table 2 and parameter values in “Row index ofnon-zero-element” in the Table 3 may be sorted in another order insteadof an ascending order, provided that a parameter value is indexed to acolumn of a non-zero-element or indexed to a row of a non-zero-element.

In an implementation, Table 2 or Table 3 may further include a column“Shift value of non-zero-element”. Parameter values in the column “Shiftvalue of non-zero-element” are in a one-to-one correspondence with theparameter values in “Column index of non-zero-element”. Table 5 mayfurther include a column “Shift value of non-zero-element”. Parametervalues in the column “Shift value of non-zero-element” are in aone-to-one correspondence with parameter values in “Row index ofnon-zero-element”.

In a design, to save storage space, a position of a non-zero-element ina part with a relatively definite structure in the base graph may becalculated according to a row position and a column index, and may notbe stored. For example, the submatrix E is a diagonal matrix, andincludes non-zero-elements only on the diagonal of the matrix. A columnindex of a non-zero-element may be calculated according to a row index,or a row index of a non-zero-element may also be calculated according toa column index. Using the base graph 30 a as an example, for a weight-1column in row m_(e), where m_(e)≥4, a column index of a non-zero-elementis column (m_(e)+K_(b)), in this case, K_(b)=10. For example, a columnindex of a non-zero-element in row 4 is column 14. For another example,the bi-diagonal structure B′ in the submatrix B is located in row 0 torow 3 and column 11 to column 13 in the base graph 30 a. A columnposition of a non-zero-element may be calculated according to a rowindex, or a row index of a non-zero-element may also be calculatedaccording to a column index. For row mB, if 0<m_(B)<3, column indexes ofnon-zero-elements in the row include column (m_(B)+K_(b)) and column(m_(B)+K_(b)+1); and if m_(B)=0 or m_(B)=3, a column index of anon-zero-element in the row includes column (m_(B)+K_(b)).

As shown in Table 4, Table 4 shows parameters in rows in the base graph30 a. Column indexes of non-zero-elements in column 0 to column 13 maybe stored. However, Column indexes of non-zero-elements in column 14 tocolumn 52 are not stored, that is, a column index of a non-zero-elementin a weight-1 column is not stored. Table 4 may be used to indicateH_(BG2) including 14 columns:

TABLE 4 Row index Row weight Column index of non-zero-element 0 8 0, 1,2, 3, 6, 9, 10, 11 1 10 0, 3, 4, 5, 6, 7, 8, 9, 11, 12 2 8 0, 1, 3, 4,8, 10, 12, 13 3 10 1, 2, 4, 5, 6, 7, 8, 9, 10, 13 4 3 0, 1, 11 5 5 0, 1,5, 7, 11 6 5 0, 5, 7, 9, 11 7 5 1, 5, 7, 11, 13 8 3 0, 1, 12 9 4 1, 8,10, 11 10 4 0, 1, 6, 7 11 4 0, 7, 9, 13 12 3 1, 3, 11 13 4 0, 1, 8, 1314 4 1, 6, 11, 13 15 3 0, 10, 11 16 4 1, 9, 11, 12 17 4 1, 5, 11, 12 183 0, 6, 7 19 3 0, 1, 10 20 3 1, 4, 11 21 3 0, 8, 13 22 2 1, 2 23 3 0, 3,5 24 3 1, 2, 9 25 2 0, 5 26 4 2, 7, 12, 13 27 2 0, 6 28 3 1, 2, 5 29 20, 4 30 4 2, 5, 7, 9 31 2 1, 13 32 3 0, 5, 12 33 3 2, 7, 10 34 3 0, 12,13 35 3 1, 5, 11 36 3 0, 2, 7 37 2 10, 13 38 3 1, 5, 11 39 3 0, 7, 12 403 2, 10, 13 41 3 1, 5, 11

Certainly, for parameters stored in H_(BG2) including 15 columns,parameters of row 0 to row 3 and column 5 to column 41 are the same asthose in Table 4. A row weight of row 4 is the row weight of row 4 inTable 4 plus 1, that is, 4. Column positions of non-zero-elements in row4 include column indexes of non-zero-elements in row 4 in Table 4 andcolumn index 4, that is, 0, 1, 11, and 14. For parameters stored inH_(BG2) including 16 columns, parameters of row 0 to row 3 and column 6to column 41 are the same as those in Table 4. A row weight of row 4 isthe row weight of row 4 in Table 4 plus 1, that is, 4. Column positionsof non-zero-elements in row 4 include column indexes ofnon-zero-elements in row 4 in Table 4 and column index 14, that is, 0,1, 11, and 14. A row weight of row 5 is the row weight of row 5 in Table4 plus 1, that is, 6. Column positions of non-zero-elements in row 5include column positions of non-zero-elements in row 5 in Table 4 and aposition whose column index is 15, that is, 0, 1, 5, 7, 11, and 15.

For parameters stored in H_(BG2) including 17 columns, parameters of row0 to row 3 and column 7 to column 41 are the same as those in Table 4. Arow weight of row 4 is the row weight of row 4 in Table 4 plus 1, thatis, 4. Column positions of non-zero-elements in row 4 include columnindexes of non-zero-elements in row 4 in Table 4 and column index 14,that is, 0, 1, 11, and 14. A row weight of row 5 is the row weight ofrow 5 in Table 4 plus 1, that is, 6. Column positions ofnon-zero-elements in row 5 include column indexes of non-zero-elementsin row 5 in Table 4 and column index 15, that is, 0, 1, 5, 7, 11, and15. A row weight of row 6 is the row weight of row 6 in Table 4 plus 1,that is, 6. Column positions of non-zero-elements in row 6 includecolumn indexes of non-zero-elements in row 6 in Table 4 and column index16, that is, 0, 5, 7, 9, 11, and 16, as shown in Table 5.

TABLE 5 Row index Row weight Column index of non-zero-element 0 8 0, 1,2, 3, 6, 9, 10, 11 1 10 0, 3, 4, 5, 6, 7, 8, 9, 11, 12 2 8 0, 1, 3, 4,8, 10, 12 13 3 10 1, 2, 4, 5, 6, 7, 8, 9, 10, 13 4 4 0, 1, 11, 14 5 6 0,1, 5, 7, 11, 15 6 6 0, 5, 7, 9, 11, 16 7 5 1, 5, 7, 11, 13 8 3 0, 1, 129 4 1, 8, 10, 11 10 4 0, 1, 6, 7 11 4 0, 7, 9, 13 12 3 1, 3, 11 13 4 0,1, 8, 13 14 4 1, 6, 11, 13 15 3 0, 10, 11 16 4 1, 9, 11, 12 17 4 1, 5,11, 12 18 3 0, 6, 7 19 3 0, 1, 10 20 3 1, 4, 11 21 3 0, 8, 13 22 2 1, 223 3 0, 3, 5 24 3 1, 2, 9 25 2 0, 5 26 4 2, 7, 12, 13 27 2 0, 6 28 3 1,2, 5 29 2 0, 4 30 4 2, 5, 7, 9 31 2 1, 13 32 3 0, 5, 12 33 3 2, 7, 10 343 0, 12, 13 35 3 1, 5, 11 36 3 0, 2, 7 37 2 10, 13 38 3 1, 5, 11 39 3 0,7, 12 40 3 2, 10, 13 41 3 1, 5, 11

In the foregoing designs, each “Row weight” column is optional. In apossible design, in the base graph, 1 and 0 in each row or each columnmay be considered as binary digits. Storage space may be saved bystoring the binary digits as decimal digits or hexadecimal digits. Usingany of the foregoing base graphs as an example, for each row, positionsof non-zero-elements in former 26 columns or former 27 columns may bestored by using four hexadecimal digits. For example, if former 14columns in row 0 are 11110010011100, positions of non-zero-elements inrow 0 may be denoted as 0xF2 and 0x70, that is, each eight columns forma hexadecimal digit. For the last two columns in row 0, a correspondinghexadecimal digit may be obtained by filling 0s to reach an integermultiple of 8 bits. Certainly, a corresponding hexadecimal digit mayalternatively be obtained by filling 0s before 11110010011100 to reachan integer multiple of 8 bits. Other rows can be deduced by analogy, anddetails are not described herein again.

It should be noted that only examples are provided herein, and theexamples do not constitute a limitation in the present application.

When the information bit sequence is encoded, the LDPC matrix H used forencoding may be obtained by expanding the base matrix H_(B) according toZ. For each non-zero-element P_(i,j) in the base matrix H_(B), acircular permutation matrix h_(i,j) of size Z×Z is determined, whereh_(i,j) is a circular permutation matrix obtained by circularly shiftingan identity matrix for P_(i,j) times. The parity check matrix H isobtained by replacing each non-zero-element P_(i,j) with h_(i,j) andreplacing each zero-element in the base matrix H_(B) with an all zeromatrix of size Z×Z.

In a communication system, an LDPC code may be obtained by encoding byusing the foregoing method. After obtaining the LDPC code, acommunication apparatus may further perform the following one or moreoperations: performing rate matching on the LDPC code; interleaving,according to an interleaving scheme, an LDPC code obtained by performingrate matching; modulating the interleaved LDPC code according to amodulation scheme to obtain a bit sequence B; and sending the bitsequence B.

In a decoding method provided in another embodiment of the presentapplication, a decoder decodes an input sequence by using an LDPCmatrix. A base graph of the LDPC matrix may be any base graph in theforegoing examples. A base matrix H_(B) of the LDPC matrix may be anybase matrix in the foregoing examples. The input sequence of the decodermay be a soft value sequence of an LDPC code.

Further, the method includes: determining a lifting factor Z. Acommunication device at a receive end may receive a signal including theLDPC code, obtain the soft value sequence of the LDPC code in thesignal, and determine the corresponding lifting factor Z.

The decoding, by a decoder, an input sequence by using an LDPC matrixmay be decoding the soft value sequence of the LDPC code by using theLDPC matrix corresponding to the lifting factor Z.

Decoding is an inverse process of encoding. Therefore, for descriptionsof the LDPC matrix H and the base graph of the LDPC matrix, refer to theforegoing encoding embodiments. During decoding, decoding mayalternatively be performed based on the complete base graph, or based onsome rows and columns of the complete base graph. The base matrix H_(B)of the LDPC matrix may be any base matrix mentioned in the foregoingembodiments or a base matrix obtained by performing row permutation, orcolumn permutation, or both row permutation and column permutation onany base matrix described above. The base graph of the LDPC matrixincludes at least a submatrix A and a submatrix B, and may furtherinclude a submatrix C, a submatrix D, and a submatrix E. For each part,refer to descriptions in the foregoing embodiments, and details are notdescribed herein again.

In a possible design, the base matrix H_(B) of the LDPC code may bestored in a memory, and soft values of the LDPC code may be decoded byobtaining the LDPC matrix corresponding to the lifting factor Z.

In another possible implementation, because there are a plurality ofbase matrices of the LDPC code, relatively large storage space isoccupied when the base matrices are stored according to matrixstructures. The base graph of the LDPC code may alternatively be storedin the memory, and shift values of non-zero-elements in the basematrices may be stored row by row or column by column, and then the LDPCmatrix may be obtained based on the base graph and shift values of thebase matrix corresponding to the lifting factor Z.

For a manner of storing the base graph, the base graph may be stored invarious manners described in the foregoing encoding embodiments. Itshould be noted that only examples are provided herein, and the examplesdo not constitute a limitation.

Decoding is a process inverse to encoding, and the base matrix H_(B)used during the decoding has a same characteristic as the base matrix inthe encoding method embodiments. For obtaining the LDPC matrix H bylifting the base matrix H_(B), refer to the encoding method embodiments.

In a communication system, before the decoding method, a communicationapparatus may further perform the following one or more operations:receiving a signal including an LDPC code, and performing demodulation,deinterleaving, and perform de-rate matching on the signal, to obtainthe soft values of the LDPC code.

In a possible implementation, one or more parameters of the followingmay be stored:

(a) parameter used to obtain any base matrix H_(B) described in theforegoing implementations. The base matrix H_(B) may be obtained basedon the parameters; for example, the parameters may include one or moreof the following: shift values in a base matrix, a lifting factor, abase graph of the base matrix, a code rate, or the like;

(b) a base matrix H_(B), which is one of any base matrices described inthe foregoing implementations;

(c) a matrix obtained after performing lifting based on the base matrixH_(B);

(d) a base matrix obtained by performing row/column permutation based onthe any base matrix H_(B) described in the foregoing implementations,where in this application, the row/column permutation refers to rowpermutation, column permutation, or row permutation and columnpermutation; and

(e) a matrix obtained by performing lifting based on the base matrixobtained by performing row/column permutation.

In a possible implementation, in an encoding process or a decodingprocess, the encoding an input sequence by using a low density paritycheck LDPC matrix may be performed in one or more of the followingmanners:

i obtaining the base matrix H_(B) based on the foregoing (a), andperforming encoding or decoding based on the obtained base matrix H_(B);or performing row/column permutation based on the obtained base matrixH_(B), and performing encoding or decoding based on a base matrixobtained by performing row/column permutation, where the performingencoding or decoding based on the base matrix may optionally furtherinclude performing encoding or decoding based on a lifted matrix of thebase matrix;

ii performing encoding or decoding based on the stored base matrix (thestored base matrix H_(B), or the stored base matrix obtained byperforming row/column permutation based on the base matrix H_(B)) in (b)or (d); or performing row/column permutation based on the stored basematrix, and performing encoding or decoding based on a base matrixobtained by performing row/column permutation, where the performingencoding or decoding based on the base matrix may optionally furtherinclude performing encoding or decoding based on a lifted matrix of thebase matrix; and

iii performing encoding or decoding based on (c) or (e).

The storing in this application may be storing in one or more memories.The one or more memories may be separately disposed, or may beintegrated into the encoder, the decoder, a processor, a chip, acommunication apparatus, or a terminal. Alternatively, some of the oneor more memories may be separately disposed, and the others areintegrated into an encoder, a decoder, a processor, a chip, acommunication apparatus, or a terminal. A type of the memory may be astorage medium in any form. This is not limited in this application.

FIG. 5 is a schematic structural diagram of a communication apparatus500. The apparatus 500 may be configured to implement the methoddescribed in the foregoing method embodiments. Reference may be made todescriptions in the foregoing method embodiments. The communicationapparatus 500 may be a chip, a base station, a terminal, or othernetwork devices.

The communication apparatus 500 includes one or more processors 501. Theprocessor 501 may be a general-purpose processor, a special-purposeprocessor, or the like. For example, the processor 501 may be a basebandprocessor or a central processing unit. The baseband processor may beconfigured to process a communication protocol and communication data.The central processing unit may be configured to: control thecommunication apparatus (such as a base station, a terminal, or a chip),execute a software program, and process data of the software program.

In a possible design, the communication apparatus 500 includes one ormore processors 501. The one or more processors 501 may implement afunction of the foregoing encoder. In another possible design, theforegoing encoder may be a part of the processor 501. In addition to thefunction of the encoder, the processor 501 may further implement anotherfunction.

The communication apparatus 500 encodes an input sequence by using anLDPC matrix. A base graph of the LDPC matrix may be any base graph inthe foregoing examples, or a base graph obtained by performing rowpermutation, column permutation, or both row permutation and columnpermutation on any base graph described above. A base matrix H_(B) ofthe LDPC matrix may be any base matrix in the foregoing embodiments, ora base matrix obtained by performing row permutation, columnpermutation, or both row permutation and column permutation on any basematrix described above. The input sequence of the encoder may be aninformation bit sequence.

In a possible design, the one or more processors 501 may implement afunction of the foregoing decoder. In another possible design, theforegoing decoder may be a part of the processor 501.

The communication apparatus 500 may be configured to decode an inputsequence by using an LDPC matrix. A base graph of the LDPC matrix may beany base graph in the foregoing examples, or a base graph obtained byperforming row permutation, column permutation, or both row permutationand column permutation on any base graph described above. A base matrixH_(B) of the LDPC matrix may be any base matrix in the foregoingexamples, or a base matrix obtained by performing row permutation,column permutation, or both row permutation and column permutation onany base matrix described above. The input sequence of the decoder maybe a soft value sequence.

In an optional possible design, the processor 501 may further includeinstruction(s) 503. The instruction(s) may be executed on the processor,so that the communication apparatus 500 performs the method described inthe foregoing method embodiments.

In another possible design, the communication apparatus 500 may furtherinclude a circuit. The circuit may implement the function of theencoder, the function of the decoder, or the functions of the encoderand the decoder in the foregoing method embodiments.

Optionally, the communication apparatus 500 may include one or morememories 502. The memory stores instruction(s) 504, and theinstruction(s) may be executed on the processor, so that thecommunication apparatus 500 performs the method described in theforegoing method embodiments. Optionally, the memory may further storedata. Optionally, the processor may further store instruction(s) and/ordata. The processor and the memory may be separately disposed, or may beintegrated together. Optionally, the one or more memories 502 may storeparameters related to a base matrix, for example, a shift value, a basegraph, a matrix obtained through lifting based on the base graph, eachrow in the base matrix, and a lifting factor. Optionally, the one ormore memories 502 may store a base matrix or a matrix obtained throughlifting based on the base matrix.

Optionally, the communication apparatus 500 may further include atransceiver 505 and an antenna 506. The processor 501 may be referred toas a processing unit. The processor 501 controls the communicationapparatus (a terminal or a base station). The transceiver 505 may bereferred to as a transceiver unit, a transceiver circuit, a transceiver,or the like, and is configured to implement transmitting and receivingfunctions of the communication apparatus by using the antenna 506.

Optionally, the communication apparatus 500 may further include acomponent configured to generate a transport block CRC, a component usedfor code block segmentation and CRC attachment, an interleaver used forinterleaving, a modulator used for modulation processing, or the like.Functions of the components may be implemented by using the one or moreprocessors 501.

Optionally, the communication apparatus 500 may further include ademodulator used for a demodulation operation, a deinterleaver used fordeinterleaving, a component used for de-rate matching, or the like.Functions of the components may be implemented by using the one or moreprocessors 501.

FIG. 6 is a schematic diagram of a communication system 600. Thecommunication system 600 includes a communication device 60 and acommunication device 61. Information data is received and sent betweenthe communication device 60 and the communication device 61. Thecommunication device 60 and the communication device 61 may be thecommunication apparatus 500, or the communication device 60 and thecommunications device 61 respectively includes a communication apparatus500 for receiving and sending the information data. In an example, thecommunication device 60 may be a terminal, and correspondingly, thecommunication device 61 may be a base station. In another example, thecommunication device 60 is a base station, and correspondingly, thecommunication device 61 may be a terminal.

A person skilled in the art may further understand that variousillustrative logical blocks and steps that are listed in the embodimentsof the present application may be implemented by using electronichardware, computer software, or a combination thereof. Whether thefunctions are implemented by using hardware or software depends onparticular applications and a design requirement of the complete system.For each specific application, a person skilled in the art may usevarious methods to implement the functions. However, this implementationshould not be understood to go beyond the protection scope of thepresent application.

The various illustrative logical units and circuits described in theembodiments of the present application may implement or operate thedescribed functions by using a general processor, a digital signalprocessor, an application-specific integrated circuit (ASIC), a fieldprogrammable gate array (FPGA) or another programmable logicalapparatus, a discrete gate or transistor logic, a discrete hardwarecomponent, or a design of any combination thereof. The general processormay be a microprocessor. Optionally, the general processor may also beany conventional processor, controller, microcontroller, or statemachine. The processor may also be implemented by a combination ofcomputing apparatuses, such as a digital signal processor and amicroprocessor, multiple microprocessors, one or more microprocessorswith a digital signal processor core, or any other similarconfiguration.

Steps of the methods or algorithms described in the embodiments of thepresent application may be directly embedded into hardware,instruction(s) executed by a processor, or a combination thereof. Thememory may be a random access memory (RAM), a flash memory, a read-onlymemory (ROM), an erasable programmable read-only memory (EPROM), anelectrically erasable programmable read-only memory (EEPROM), aregister, a hard disk, a removable magnetic disk, a CD-ROM, or a storagemedium of any other form in the art. For example, the memory may connectto a processor so that the processor may read information from thememory and write information to the memory. Alternatively, the memorymay further be integrated into a processor. The processor and the memorymay be disposed in an ASIC, and the ASIC may be disposed in a userequipment (UE). Alternatively, the processor and the memory may bedisposed in different components of UE.

With descriptions of the foregoing embodiments, a person skilled in theart may clearly understand that the present application may beimplemented by hardware, firmware or a combination thereof When thepresent application is implemented by using a software program, all or apart of the present application may be implemented in a form of acomputer program product. The computer program product includes one ormore computer instructions. When the computer instructions are loadedand executed on the computer, the procedures or functions according tothe embodiments of the present application are all or partiallygenerated. When the present application is implemented by the softwareprogram, the foregoing functions may be stored in a computer-readablemedium or transmitted as one or more instructions or code in thecomputer-readable medium. The computer may be a general-purposecomputer, a dedicated computer, a computer network, or anotherprogrammable apparatus. The computer instructions may be stored in acomputer-readable storage medium or may be transmitted from acomputer-readable storage medium to another computer-readable storagemedium. The computer-readable medium includes a computer storage mediumand a communication medium, where the communication medium includes anymedium that enables a computer program to be transmitted from one placeto another. The storage medium may be any available medium accessible toa computer. The following provides an example but does not impose alimitation: The computer-readable medium may include a RAM, a ROM, anEEPROM, a CD-ROM, or another optical disc storage or disk storagemedium, or another magnetic storage device, or any other medium that cancarry or store expected program code in a form of instruction(s) or adata structure and can be accessed by a computer. In addition, anyconnection may be appropriately defined as a computer-readable medium.For example, if software is transmitted from a website, a server oranother remote source by using a coaxial cable, an optical fiber/cable,a twisted pair, a digital subscriber line (DSL) or wireless technologiessuch as infrared ray, radio and microwave, the coaxial cable, opticalfiber/cable, twisted pair, DSL or wireless technologies such as infraredray, radio and microwave are included in fixation of a medium to whichthey belong. For example, a disk and disc used by the presentapplication includes a compact disc (CD), a laser disc, an optical disc,a digital versatile disc (DVD), a floppy disk and a Blue-ray disc, wherethe disk generally copies data by a magnetic means, and the disc copiesdata optically by a laser means. The foregoing combination should alsobe included in the protection scope of the computer-readable medium.

Described herein are merely examples of embodiments of technicalsolutions of the present application, and the description of theexamples is not intended to limit the protection scope of the presentapplication. Any modification, equivalent replacement, or improvementmade without departing from principles of the present application mayfall within the protection scope of the present application.

What is claimed is:
 1. A method for wireless communication, comprising:obtaining, by a communication apparatus, an input sequence; decoding, bythe communication apparatus, the input sequence using a matrix H toobtain a decoded sequence, wherein the decoded sequence comprises Kbits, wherein K≥1; and outputting, by the communication apparatus, thedecoded sequence; wherein the matrix H is determined according to a basematrix and a lifting factor Z, wherein Z is a positive integer; whereinthe base matrix comprises m rows and n columns; wherein each element inthe base matrix has a row index i and a column index j, where 0≤i<m and0≤j<n; wherein each element in the base matrix is either a zero-elementor a non-zero-element; wherein the base matrix comprises following rows:a first row corresponding to row index i=0 having non-zero-elements atcolumns corresponding to column indexes j=0, 1, 2, 3, 6, 9, 10, 11; asecond row corresponding to row index i=1 having non-zero-elements atcolumns corresponding to column indexes j=0, 3, 4, 5, 6, 7, 8, 9, 11,12; a third row corresponding to row index i=2 having non-zero-elementsat columns corresponding to column indexes j=0, 1, 3, 4, 8, 10, 12, 13;and a fourth row corresponding to row index i=3 having non-zero-elementsat columns corresponding to column indexes j=1, 2, 4, 5, 6, 7, 8, 9, 10,13.
 2. The method according to claim 1, wherein each zero-element in thebase matrix corresponds to an all-zero matrix of size Z×Z in the matrixH; wherein a non-zero-element with a row index i and a column index jhas a value V_(i,j) and corresponds to a circular permutation matrixI(P_(i,j)) of size Z×Z in the matrix H; and wherein P_(i,j) is aninteger shift value greater than or equal to zero, and P_(i,j)=mod(V_(i,j),Z).
 3. The method according to claim 1, wherein K=10×Z.
 4. Themethod according to claim 1, wherein the lifting factor Z satisfiesZ=a×2^(j), where a ∈ {2, 3, 5, 7, 9,11,13,15}, and wherein: in case ofa=2, j=0, 1, 2, 3, 4, 5, 6 or 7; in case of a=3, j=0, 1, 2, 3, 4, 5, 6or 7; in case of a=5, j=0, 1, 2, 3, 4, 5 or 6; in case of a=7, j=0, 1,2, 3, 4 or 5; in case of a=9, j=0, 1, 2, 3, 4 or 5; in case of a=11,j=0, 1, 2, 3, 4 or 5; in case of a=13, j=0, 1, 2, 3 or 4; or in case ofa=15, j=0, 1, 2, 3 or
 4. 5. The method according to claim 1, wherein thelifting factor Z=Z₀, wherein Z₀ is a minimum of a plurality of liftingfactors satisfying a relationship of Kb×Z₀≥K, and Kb is one of {6, 8, 9,10}.
 6. The method according to claim 5, wherein: in case of K>640, Kbis equal to 10; or in case of K>560 and K≤640, Kb is equal to 9; or incase of K>192 and K≤560, Kb is equal to 8; or in case of K≤192, Kb isequal to
 6. 7. The method according to claim 1, wherein the base matrixfurther comprises at least one of the following rows: a fifth rowcorresponding to row index i=4 having non-zero-elements at columnscorresponding to column indexes j=0, 1, 11, 14; a sixth rowcorresponding to row index i=5 having non-zero-elements at columnscorresponding to column indexes j=0, 1, 5, 7, 11, 15; a seventh rowcorresponding to row index i=6 having non-zero-elements at columnscorresponding to column indexes j=0, 5, 7, 9, 11, 16; an eighth rowcorresponding to row index i=7 having non-zero-elements at columnscorresponding to column indexes j=1, 5, 7, 11, 13, 17; a ninth rowcorresponding to row index i=8 having non-zero-elements at columnscorresponding to column indexes j=0, 1, 12, 18; a tenth rowcorresponding to row index i=9 having non-zero-elements at columnscorresponding to column indexes j=1, 8, 10, 11, 19; an eleventh rowcorresponding to row index i=10 having non-zero-elements at columnscorresponding to column indexes j=0, 1, 6, 7, 20; a twelfth rowcorresponding to row index i=11 having non-zero-elements at columnscorresponding to column indexes j=0, 7, 9, 13, 21; a thirteenth rowcorresponding to row index i=12 having non-zero-elements at columnscorresponding to column indexes j=1, 3, 11, 22; a fourteenth rowcorresponding to row index i=13 having non-zero-elements at columnscorresponding to column indexes j=0, 1, 8, 13, 23; a fifteenth rowcorresponding to row index i=14 having non-zero-elements at columnscorresponding to column indexes j=1, 6, 11, 13, 24; a sixteenth rowcorresponding to row index i=15 having non-zero-elements at columnscorresponding to column indexes j=0, 10, 11, 25; a seventeenth rowcorresponding to row index i=16 having non-zero-elements at columnscorresponding to column indexes j=1, 9, 11, 12, 26; an eighteenth rowcorresponding to row index i=17 having non-zero-elements at columnscorresponding to column indexes j=1, 5, 11, 12, 27; a nineteenth rowcorresponding to row index i=18 having non-zero-elements at columnscorresponding to column indexes j=0, 6, 7, 28; a twentieth rowcorresponding to row index i=19 having non-zero-elements at columnscorresponding to column indexes j=0, 1, 10, 29; a twenty-first rowcorresponding to row index i=20 having non-zero-elements at columnscorresponding to column indexes j=1, 4, 11, 30; a twenty-second rowcorresponding to row index i=21 having non-zero-elements at columnscorresponding to column indexes j=0, 8, 13, 31; a twenty-third rowcorresponding to row index i=22 having non-zero-elements at columnscorresponding to column indexes j=1, 2, 32; a twenty-fourth rowcorresponding to row index i=23 having non-zero-elements at columnscorresponding to column indexes j=0, 3, 5, 33; a twenty-fifth rowcorresponding to row index i=24 having non-zero-elements at columnscorresponding to column indexes j=1, 2, 9, 34; a twenty-sixth rowcorresponding to row index i=25 having non-zero-elements at columnscorresponding to column indexes j=0, 5, 35; a twenty-seventh rowcorresponding to row index i=26 having non-zero-elements at columnscorresponding to column indexes j=2, 7, 12, 13, 36; a twenty-eighth rowcorresponding to row index i=27 having non-zero-elements at columnscorresponding to column indexes j=0, 6, 37; a twenty-ninth rowcorresponding to row index i=28 having non-zero-elements at columnscorresponding to column indexes j=1, 2, 5, 38; a thirtieth rowcorresponding to row index i=29 having non-zero-elements at columnscorresponding to column indexes j=0, 4, 39; a thirty-first rowcorresponding to row index i=30 having non-zero-elements at columnscorresponding to column indexes j=2, 5, 7, 9, 40; a thirty-second rowcorresponding to row index i=31 having non-zero-elements at columnscorresponding to column indexes j=1, 13, 41; a thirty-third rowcorresponding to row index i=32 having non-zero-elements at columnscorresponding to column indexes j=0, 5, 12, 42; a thirty-fourth rowcorresponding to row index i=33 having non-zero-elements at columnscorresponding to column indexes j=2, 7, 10, 43; a thirty-fifth rowcorresponding to row index i=34 having non-zero-elements at columnscorresponding to column indexes j=0, 12, 13, 44; a thirty-sixth rowcorresponding to row index i=35 having non-zero-elements at columnscorresponding to column indexes j=1, 5, 11, 45; a thirty-seventh rowcorresponding to row index i=36 having non-zero-elements at columnscorresponding to column indexes j=0, 2, 7, 46; a thirty-eighth rowcorresponding to row index i=37 having non-zero-elements at columnscorresponding to column indexes j=10, 13, 47; a thirty-ninth rowcorresponding to row index i=38 having non-zero-elements at columnscorresponding to column indexes j=1, 5, 11, 48; a fortieth rowcorresponding to row index i=39 having non-zero-elements at columnscorresponding to column indexes j=0, 7, 12, 49; a forty-first rowcorresponding to row index i=40 having non-zero-elements at columnscorresponding to column indexes j=2, 10, 13, 50; or a forty-second rowcorresponding to row index i=41 having non-zero-elements at columnscorresponding to column indexes j=1, 5, 11,
 51. 8. The method accordingto claim 1, wherein the matrix H is determined according to a permutatedmatrix of the base matrix, and wherein the permutated matrix is obtainedby performing row permutation and/or column permutation on the basematrix.
 9. The method according to claim 1, wherein n=m+10.
 10. Themethod according to claim 1, wherein 4≤m≤42 and 14≤n≤52.
 11. Anapparatus for wireless communication, comprising at least one processorconfigured to: obtain an input sequence; decode the input sequence usinga matrix H to obtain a decoded sequence, wherein the decoded sequencecomprises K bits, wherein K≥1; and output the decoded sequence; whereinthe matrix H is based on a base matrix and a lifting factor Z, wherein Zis a positive integer; wherein the base matrix comprises m rows and ncolumns; wherein each element in the base matrix has a row index i and acolumn index j, where 0≤i<m and 0≤j<n; wherein each element in the basematrix is either a zero-element or a non-zero-element; wherein the basematrix comprises following rows: a first row corresponding to row indexi=0 having non-zero-elements at columns corresponding to column indexesj=0, 1, 2, 3, 6, 9, 10, 11; a second row corresponding to row index i=1having non-zero-elements at columns corresponding to column indexes j=0,3, 4, 5, 6, 7, 8, 9, 11, 12; a third row corresponding to row index i=2having non-zero-elements at columns corresponding to column indexes j=0,1, 3, 4, 8, 10, 12, 13; and a fourth row corresponding to row index i=3having non-zero-elements at columns corresponding to column indexes j=1,2, 4, 5, 6, 7, 8, 9, 10,
 13. 12. The apparatus according to claim 11,wherein each zero-element in the base matrix corresponds to an all-zeromatrix of size Z×Z in the matrix H; wherein a non-zero-element with arow index i and a column index j has a value V_(i,j) and corresponds toa circular permutation matrix I(P_(i,j)) of size Z×Z in the matrix H;and wherein P_(i,j) is an integer shift value greater than or equal tozero, and P_(i,j)=mod (V_(i,j),Z).
 13. The apparatus according to claim11, wherein K=10×Z.
 14. The apparatus according to claim 11, wherein thelifting factor Z satisfies Z=a×2^(j), where a ∈ {2,3, 5, 7, 9,11,13,15},wherein: in case of a=2, j=0, 1, 2, 3, 4, 5, 6 or 7; in case of a=3,j=0, 1, 2, 3, 4, 5, 6 or 7; in case of a=5, j=0, 1, 2, 3, 4, 5 or 6; incase of a=7, j=0, 1, 2, 3, 4 or 5; in case of a=9, j=0, 1, 2, 3, 4 or 5;in case of a=11, j=0, 1, 2, 3, 4 or 5; in case of a=13, j=0, 1, 2, 3 or4; or in case of a=15, j=0, 1, 2, 3 or
 4. 15. The apparatus according toclaim 11, wherein the lifting factor Z=Z₀, wherein Z₀ is a minimum of aplurality of lifting factors satisfying a relationship of Kb×Z₀≥K, andKb is one of {6, 8, 9, 10}.
 16. The apparatus according to claim 15,wherein: in case of K>640, Kb is equal to 10; or in case of K>560 andK≤640, Kb is equal to 9; or in case of K>192 and K≤560, Kb is equal to8; or in case of K≤192, Kb is equal to
 6. 17. The apparatus according toclaim 11, wherein the base matrix further comprises at least one of thefollowing rows: a fifth row corresponding to row index i=4 havingnon-zero-elements at columns corresponding to column indexes j=0, 1, 11,14; a sixth row corresponding to row index i=5 having non-zero-elementsat columns corresponding to column indexes j=0, 1, 5, 7, 11, 15; aseventh row corresponding to row index i=6 having non-zero-elements atcolumns corresponding to column indexes j=0, 5, 7, 9, 11, 16; an eighthrow corresponding to row index i=7 having non-zero-elements at columnscorresponding to column indexes j=1, 5, 7, 11, 13, 17; a ninth rowcorresponding to row index i=8 having non-zero-elements at columnscorresponding to column indexes j=0, 1, 12, 18; a tenth rowcorresponding to row index i=9 having non-zero-elements at columnscorresponding to column indexes j=1, 8, 10, 11, 19; an eleventh rowcorresponding to row index i=10 having non-zero-elements at columnscorresponding to column indexes j=0, 1, 6, 7, 20; a twelfth rowcorresponding to row index i=11 having non-zero-elements at columnscorresponding to column indexes j=0, 7, 9, 13, 21; a thirteenth rowcorresponding to row index i=12 having non-zero-elements at columnscorresponding to column indexes j=1, 3, 11, 22; a fourteenth rowcorresponding to row index i=13 having non-zero-elements at columnscorresponding to column indexes j=0, 1, 8, 13, 23; a fifteenth rowcorresponding to row index i=14 having non-zero-elements at columnscorresponding to column indexes j=1, 6, 11, 13, 24; a sixteenth rowcorresponding to row index i=15 having non-zero-elements at columnscorresponding to column indexes j=0, 10, 11, 25; a seventeenth rowcorresponding to row index i=16 having non-zero-elements at columnscorresponding to column indexes j=1, 9, 11, 12, 26; an eighteenth rowcorresponding to row index i=17 having non-zero-elements at columnscorresponding to column indexes j=1, 5, 11, 12, 27; a nineteenth rowcorresponding to row index i=18 having non-zero-elements at columnscorresponding to column indexes j=0, 6, 7, 28; a twentieth rowcorresponding to row index i=19 having non-zero-elements at columnscorresponding to column indexes j=0, 1, 10, 29; a twenty-first rowcorresponding to row index i=20 having non-zero-elements at columnscorresponding to column indexes j=1, 4, 11, 30; a twenty-second rowcorresponding to row index i=21 having non-zero-elements at columnscorresponding to column indexes j=0, 8, 13, 31; a twenty-third rowcorresponding to row index i=22 having non-zero-elements at columnscorresponding to column indexes j=1, 2, 32; a twenty-fourth rowcorresponding to row index i=23 having non-zero-elements at columnscorresponding to column indexes j=0, 3, 5, 33; a twenty-fifth rowcorresponding to row index i=24 having non-zero-elements at columnscorresponding to column indexes j=1, 2, 9, 34; a twenty-sixth rowcorresponding to row index i=25 having non-zero-elements at columnscorresponding to column indexes j=0, 5, 35; a twenty-seventh rowcorresponding to row index i=26 having non-zero-elements at columnscorresponding to column indexes j=2, 7, 12, 13, 36; a twenty-eighth rowcorresponding to row index i=27 having non-zero-elements at columnscorresponding to column indexes j=0, 6, 37; a twenty-ninth rowcorresponding to row index i=28 having non-zero-elements at columnscorresponding to column indexes j=1, 2, 5, 38; a thirtieth rowcorresponding to row index i=29 having non-zero-elements at columnscorresponding to column indexes j=0, 4, 39; a thirty-first rowcorresponding to row index i=30 having non-zero-elements at columnscorresponding to column indexes j=2, 5, 7, 9, 40; a thirty-second rowcorresponding to row index i=31 having non-zero-elements at columnscorresponding to column indexes j=1, 13, 41; a thirty-third rowcorresponding to row index i=32 having non-zero-elements at columnscorresponding to column indexes j=0, 5, 12, 42; a thirty-fourth rowcorresponding to row index i=33 having non-zero-elements at columnscorresponding to column indexes j=2, 7, 10, 43; a thirty-fifth rowcorresponding to row index i=34 having non-zero-elements at columnscorresponding to column indexes j=0, 12, 13, 44; a thirty-sixth rowcorresponding to row index i=35 having non-zero-elements at columnscorresponding to column indexes j=1, 5, 11, 45; a thirty-seventh rowcorresponding to row index i=36 having non-zero-elements at columnscorresponding to column indexes j=0, 2, 7, 46; a thirty-eighth rowcorresponding to row index i=37 having non-zero-elements at columnscorresponding to column indexes j=10, 13, 47; a thirty-ninth rowcorresponding to row index i=38 having non-zero-elements at columnscorresponding to column indexes j=1, 5, 11, 48; a fortieth rowcorresponding to row index i=39 having non-zero-elements at columnscorresponding to column indexes j=0, 7, 12, 49; a forty-first rowcorresponding to row index i=40 having non-zero-elements at columnscorresponding to column indexes j=2, 10, 13, 50; or a forty-second rowcorresponding to row index i=41 having non-zero-elements at columnscorresponding to column indexes j=1, 5, 11,
 51. 18. The apparatusaccording to claim 11, further comprising: one or more memoriesconfigured to store the base matrix, one or more lifting factors Z, orone or more circular permutation matrices.
 19. The apparatus accordingto claim 11, wherein the decoding is performed by using a min-sum (MS)decoding method or a belief propagation decoding method.
 20. Theapparatus according to claim 11, wherein n=m+10.
 21. The apparatusaccording to claim 11, wherein 4≤m≤42 and 14≤n≤52.
 22. A non-transitorycomputer-readable storage medium having processor-executableinstructions stored thereon, wherein the processor-executableinstructions, when executed, facilitate: obtaining an input sequence;decoding the input sequence using a matrix H to obtain a decodedsequence, wherein the decoded sequence comprises K bits, wherein K≥1;and outputting the decoded sequence; wherein the matrix H is based on abase matrix and a lifting factor Z, wherein Z is a positive integer;wherein the base matrix comprises m rows and n columns; wherein eachelement in the base matrix has a row index i and a column index j, where0≤i<m and 0≤j<n; wherein each element in the base matrix is either azero-element or a non-zero-element; wherein the base matrix comprisesfollowing rows: a first row corresponding to row index i=0 havingnon-zero-elements at columns corresponding to column indexes j=0, 1, 2,3, 6, 9, 10, 11; a second row corresponding to row index i=1 havingnon-zero-elements at columns corresponding to column indexes j=0, 3, 4,5, 6, 7, 8, 9, 11, 12; a third row corresponding to row index i=2 havingnon-zero-elements at columns corresponding to column indexes j=0, 1, 3,4, 8, 10, 12, 13; and a fourth row corresponding to row index i=3 havingnon-zero-elements at columns corresponding to column indexes j=1, 2, 4,5, 6, 7, 8, 9, 10,
 13. 23. The non-transitory computer-readable storagemedium according to claim 22, wherein each zero-element in the basematrix corresponds to an all-zero matrix of size Z×Z in the matrix H;wherein a non-zero-element with a row index i and a column index j has avalue V_(i,j) and corresponds to a circular permutation matrixI(P_(i,j)) of size Z×Z in the matrix H; and wherein P_(i,j) is aninteger shift value greater than or equal to zero, and P_(i,j)=mod(V_(i,j),Z).
 24. The non-transitory computer-readable storage mediumaccording to claim 22, wherein the base matrix further comprises atleast one of the following rows: a fifth row corresponding to row indexi=4 having non-zero-elements at columns corresponding to column indexesj=0, 1, 11, 14; a sixth row corresponding to row index i=5 havingnon-zero-elements at columns corresponding to column indexes j=0, 1, 5,7, 11, 15; a seventh row corresponding to row index i=6 havingnon-zero-elements at columns corresponding to column indexes j=0, 5, 7,9, 11, 16; an eighth row corresponding to row index i=7 havingnon-zero-elements at columns corresponding to column indexes j=1, 5, 7,11, 13, 17; a ninth row corresponding to row index i=8 havingnon-zero-elements at columns corresponding to column indexes j=0, 1, 12,18; a tenth row corresponding to row index i=9 having non-zero-elementsat columns corresponding to column indexes j=1, 8, 10, 11, 19; aneleventh row corresponding to row index i=10 having non-zero-elements atcolumns corresponding to column indexes j=0, 1, 6, 7, 20; a twelfth rowcorresponding to row index i=11 having non-zero-elements at columnscorresponding to column indexes j=0, 7, 9, 13, 21; a thirteenth rowcorresponding to row index i=12 having non-zero-elements at columnscorresponding to column indexes j=1, 3, 11, 22; a fourteenth rowcorresponding to row index i=13 having non-zero-elements at columnscorresponding to column indexes j=0, 1, 8, 13, 23; a fifteenth rowcorresponding to row index i=14 having non-zero-elements at columnscorresponding to column indexes j=1, 6, 11, 13, 24; a sixteenth rowcorresponding to row index i=15 having non-zero-elements at columnscorresponding to column indexes j=0, 10, 11, 25; a seventeenth rowcorresponding to row index i=16 having non-zero-elements at columnscorresponding to column indexes j=1, 9, 11, 12, 26; an eighteenth rowcorresponding to row index i=17 having non-zero-elements at columnscorresponding to column indexes j=1, 5, 11, 12, 27; a nineteenth rowcorresponding to row index i=18 having non-zero-elements at columnscorresponding to column indexes j=0, 6, 7, 28; a twentieth rowcorresponding to row index i=19 having non-zero-elements at columnscorresponding to column indexes j=0, 1, 10, 29; a twenty-first rowcorresponding to row index i=20 having non-zero-elements at columnscorresponding to column indexes j=1, 4, 11, 30; a twenty-second rowcorresponding to row index i=21 having non-zero-elements at columnscorresponding to column indexes j=0, 8, 13, 31; a twenty-third rowcorresponding to row index i=22 having non-zero-elements at columnscorresponding to column indexes j=1, 2, 32; a twenty-fourth rowcorresponding to row index i=23 having non-zero-elements at columnscorresponding to column indexes j=0, 3, 5, 33; a twenty-fifth rowcorresponding to row index i=24 having non-zero-elements at columnscorresponding to column indexes j=1, 2, 9, 34; a twenty-sixth rowcorresponding to row index i=25 having non-zero-elements at columnscorresponding to column indexes j=0, 5, 35; a twenty-seventh rowcorresponding to row index i=26 having non-zero-elements at columnscorresponding to column indexes j=2, 7, 12, 13, 36; a twenty-eighth rowcorresponding to row index i=27 having non-zero-elements at columnscorresponding to column indexes j=0, 6, 37; a twenty-ninth rowcorresponding to row index i=28 having non-zero-elements at columnscorresponding to column indexes j=1, 2, 5, 38; a thirtieth rowcorresponding to row index i=29 having non-zero-elements at columnscorresponding to column indexes j=0, 4, 39; a thirty-first rowcorresponding to row index i=30 having non-zero-elements at columnscorresponding to column indexes j=2, 5, 7, 9, 40; a thirty-second rowcorresponding to row index i=31 having non-zero-elements at columnscorresponding to column indexes j=1, 13, 41; a thirty-third rowcorresponding to row index i=32 having non-zero-elements at columnscorresponding to column indexes j=0, 5, 12, 42; a thirty-fourth rowcorresponding to row index i=33 having non-zero-elements at columnscorresponding to column indexes j=2, 7, 10, 43; a thirty-fifth rowcorresponding to row index i=34 having non-zero-elements at columnscorresponding to column indexes j=0, 12, 13, 44; a thirty-sixth rowcorresponding to row index i=35 having non-zero-elements at columnscorresponding to column indexes j=1, 5, 11, 45; a thirty-seventh rowcorresponding to row index i=36 having non-zero-elements at columnscorresponding to column indexes j=0, 2, 7, 46; a thirty-eighth rowcorresponding to row index i=37 having non-zero-elements at columnscorresponding to column indexes j=10, 13, 47; a thirty-ninth rowcorresponding to row index i=38 having non-zero-elements at columnscorresponding to column indexes j=1, 5, 11, 48; a fortieth rowcorresponding to row index i=39 having non-zero-elements at columnscorresponding to column indexes j=0, 7, 12, 49; a forty-first rowcorresponding to row index i=40 having non-zero-elements at columnscorresponding to column indexes j=2, 10, 13, 50; or a forty-second rowcorresponding to row index i=41 having non-zero-elements at columnscorresponding to column indexes j=1, 5, 11,
 51. 25. The non-transitorycomputer-readable storage medium according to claim 22, wherein thelifting factor Z satisfies Z=a×2^(j), where a ∈ {2,3,5,7,9,11,13,15},wherein: in case of a=2, j=0, 1, 2, 3, 4, 5, 6 or 7; in case of a=3,j=0, 1, 2, 3, 4, 5, 6 or 7; in case of a=5, j=0, 1, 2, 3, 4, 5 or 6; incase of a=7, j=0, 1, 2, 3, 4 or 5; in case of a=9, j=0, 1, 2, 3, 4 or 5;in case of a=11, j=0, 1, 2, 3, 4 or 5; in case of a=13, j=0, 1, 2, 3 or4; or in case of a=15, j=0, 1, 2, 3 or
 4. 26. The non-transitorycomputer-readable storage medium according to claim 22, wherein thelifting factor Z=Z₀, wherein Z₀ is a minimum of a plurality of liftingfactors satisfying a relationship of Kb×Z₀≥K, and Kb is one of {6, 8, 9,10}.
 27. The non-transitory computer-readable storage medium accordingto claim 22, wherein: in case of K>640, Kb is equal to 10; or in case ofK>560 and K≤640, Kb is equal to 9; or in case of K>192 and K≤560, Kb isequal to 8; or in case of K≤192, Kb is equal to
 6. 28. Thenon-transitory computer-readable storage medium according to claim 22,wherein n=m+10.
 29. The non-transitory computer-readable storage mediumaccording to claim 22, wherein K=10×Z.
 30. The non-transitorycomputer-readable storage medium according to claim 22, wherein 4≤m≤42and 14≤n≤52.